I’m using Network Framework with UDP and calling: connection.receive(minimumIncompleteLength: 1, maximumLength: 1500) { data, context, isComplete, error in ... // Some Logic } Is it possible for this completion handler to be called with data==nil if I haven't received any kind of error, i.e., error==nil and the connection is still in the .ready state?

I have an iOS app with a network extension that's using OSLog to log various bits of information that are useful for debugging. I'm currently trying to add a simple button that bundles up those logs with some other information and presents the user with a Share sheet so they can send it to support teams. I looked at OSLogStore but it only collects logs for the current process so the user clicking a button in my app wouldn't collect logs from my network extension. I would really like to avoid having to guide users through the process of creating and sharing a sysdiagnose but it seems like this might be the only option. How do other folks do this kind of thing? Is there a recommended way to do it?

My application installs a system extension. When I try to remove the app from the Applications folder (cmd + backspace) I get an error message: "The operation can’t be completed right now because another operation is in progress, such as moving or copying an item or emptying the Bin." According to systemextensionsctl the extension state is "terminating for uninstall but still running". I can see an error in the console logs: kernelmanagerd Failed to terminate dext com.my.driver-dk, error: Kernel request failed: (os/kern) invalid address (1) sysextd a category delegate declined to terminate extension with identifier: com.my.driver-dk sysextd failed to terminate extension with identifier: com.my.driver-dk: Optional(Error Domain=kernelmanagerd.KMError Code=38 "(null)") Issue occurs with macOS 13 - works fine with macOS 12 and macOS 11 What is the problem here? Have there been any changes in macOS in that regard?

I’m building a macOS app with a DNS Proxy system extension for Developer ID + notarization, deployed via MDM, and Xcode fails the Developer ID Release build with a provisioning profile mismatch for com.apple.developer.networking.networkextension. Environment macOS: Sequoia (15.7.2) Xcode: 26.2 Distribution: Developer ID + notarization, deployed via MDM Host bundle ID: com.mydns.agent.MyDNSMacProxy DNS Proxy system extension bundle ID: com.mydns.agent.MyDNSMacProxy.dnsProxy Host entitlements (Release): File: MyDNSMacProxy/MyDNSMacProxyRelease.entitlements: "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>com.apple.application-identifier</key> <string>B234657989.com.mydns.agent.MyDNSMacProxy</string> <key>com.apple.developer.networking.networkextension</key> <array> <string>dns-proxy</string> </array> <key>com.apple.developer.system-extension.install</key> <true/> <key>com.apple.developer.team-identifier</key> <string>B234657989</string> <key>com.apple.security.app-sandbox</key> <true/> <key>com.apple.security.application-groups</key> <array> <string>group.com.mydns.MyDNSmac</string> </array> <key>keychain-access-groups</key> <array> <string>B234657989.*</string> </array> </dict> </plist> xcodebuild -showBuildSettings -scheme MyDNSMacProxy -configuration Release : PROVISIONING_PROFILE_SPECIFIER = main MyDNSMacProxy5 CODE_SIGN_IDENTITY = Developer ID Application Host Developer ID profile main_MyDNSMacProxy5.provisionprofile (via security cms -D): "Entitlements" => { "com.apple.application-identifier" => "B234657989.com.mydns.agent.MyDNSMacProxy" "com.apple.developer.team-identifier" => "B234657989" "com.apple.security.application-groups" => [ "group.com.mydns.MyDNSmac", ..., "B234657989.*" ] "keychain-access-groups" => [ "B234657989.*" ] "com.apple.developer.system-extension.install" => 1 "com.apple.developer.networking.networkextension" => [ "packet-tunnel-provider-systemextension", "app-proxy-provider-systemextension", "content-filter-provider-systemextension", "dns-proxy-systemextension", "dns-settings", "relay", "url-filter-provider", "hotspot-provider" ] } So: App ID, team ID, keychain and system‑extension.install match. The profile’s com.apple.developer.networking.networkextension is a superset of what I request in the host entitlements (dns-proxy only). System extension (for context) DNS Proxy system extension target: NSExtensionPointIdentifier = com.apple.dns-proxy NetworkExtension → NEProviderClasses → com.apple.networkextension.dns-proxy → my provider class Entitlements: com.apple.developer.networking.networkextension = ["dns-proxy-systemextension"] This target uses a separate Developer ID profile and builds successfully. Xcode error Release build of the host fails with: …MyDNSMacProxy.xcodeproj: error: Provisioning profile "main MyDNSMacProxy5" doesn't match the entitlements file's value for the com.apple.developer.networking.networkextension entitlement. (in target 'MyDNSMacProxy' from project 'MyDNSMacProxy') Xcode UI also says: Entitlements: 6 Included, 1 Missing Includes com.apple.developer.team-identifier, com.apple.application-identifier, keychain-access-groups, com.apple.developer.system-extension.install, and com.apple.security.application-groups. Doesn’t match entitlements file value for com.apple.developer.networking.networkextension. Because of this, the app bundle isn’t produced and I can’t inspect the final signed entitlements. Questions: For com.apple.developer.networking.networkextension, should Xcode accept a subset of values in the entitlements (here just dns-proxy) as long as that value is allowed by the Developer ID profile, or does it currently require a stricter match? Is the following configuration valid for Developer ID + MDM with a DNS Proxy system extension: Host entitlements: ["dns-proxy"] System extension entitlements: ["dns-proxy-systemextension"] Host profile’s NE array includes the DNS Proxy system extension types. If this is a known limitation or bug in how Xcode validates NE entitlements for Developer ID, is there a recommended workaround? Thanks for any guidance.

How to legally and compliantly upload users' fitness and health data to our own server—while adhering to Apple's strict privacy policies—for analysis by our AI large model to provide personalized feedback and recommendations to users.

Hi, I’m implementing a NetworkExtension content filter provider on iOS and I can’t get it to activate on device. I have an iOS app (App Store distribution) with a content filter provider extension (NEFilterDataProvider). The app builds, installs, and runs fine, and the extension is embedded correctly. Entitlements appear to be set for both the app and the extension, and the extension’s Info.plist is configured as expected. However, when I try to enable the filter via NEFilterManager (loadFromPreferences → set configuration → isEnabled = true → saveToPreferences), saveToPreferences fails with NEFilterErrorDomain code 1 and the message “Configuration invalid or read/write failed.” The extension never starts and startFilter() is never called. Main app bundle ID: uk.co.getnovi.student Extension bundle ID: uk.co.getnovi.student.NoviContentFilter Extension type: NEFilterDataProvider We are testing on an iPhone 15 running iOS 18.6.2 (22G100), the app is designed to run on iPhone. This app is intended for education use on student-owned personal iPhones installed from the App Store. The devices we are testing on are not supervised and not enrolled in MDM. We already use the Family Controls framework (ManagedSettings) for app restrictions and have the com.apple.developer.family-controls entitlement enabled for App Store distribution. I’ve read TN3134 and noticed content filter providers on iOS are described as “supervised devices only” in general, with additional notes around iOS 15.0 for “apps using Screen Time APIs” and iOS 16.0 for “per-app on managed devices,” plus a note that in the Screen Time case content filters are only supported on child devices. My question is whether this error is what you’d expect when attempting to enable a content filter provider on a non-supervised, non-managed device, or whether this should still work if the entitlement and configuration are correct. If non-supervised devices are not supported, is there any supported path for enabling NEFilter on iOS without supervision/MDM (for example via the Screen Time / Family Controls child authorization pathway), or will the system always refuse to enable the filter on standard devices? In summary: is NEFilterDataProvider supported on non-supervised devices for consumer App Store apps, or is this a platform restriction that cannot be worked around? Thanks, Matt

Background: My app uses a third-party SDK for payments, and it uses Original StoreKit internally for IAP payments. Now I'm getting ready to migrate to StoreKit2, and during the transition, users may use either method to initiate payments, and there's no way to avoid the coexistence of StoreKit2 and Original StoreKit. Problem: When a user has an unfinished transaction, if the app is restarted, both StoreKit2 and Original StoreKit will receive a notification of the transaction: Original StoreKit's '-paymentQueue:updatedTransactions:' method StoreKit2's 'Transaction.updated' method resulting in duplicate calls to the shipping API. My current treatment is to only add '-paymentQueue:updatedTransactions:' to listen for unfinished transactions. Even if the user is using StoreKit2 to initiate the payment, if the transaction is not Finished, it will be fetched via this method after restarting the app to process this transaction. Is this approach feasible and are there any best practices for this scenario? To summarize: Is it feasible to fetch unfinished StoreKit2 transactions via Original StoreKit methods when StoreKit2 coexists with Original StoreKit? Is there a recommended way

Hi, I tried to follow this guide: https://developer.apple.com/documentation/networkextension/filtering-traffic-by-url And this: https://github.com/apple/pir-service-example I already deploy the pir service on my server. And set the configuration on the app like this: { name = SimpleURLFilter identifier = xxxxx applicationName = SimpleURLFilter application = com.xxxx.SimpleURLFilter grade = 2 urlFilter = { Enabled = YES FailClosed = NO AppBundleIdentifier = com.mastersystem.SimpleURLFilter ControlProviderBundleIdentifier = com.xxxx.SimpleURLFilter.SimpleURLFilterExtension PrefilterFetchFrequency = 2700 pirServerURL = https://xxxxx/pir pirPrivacyPassIssuerURL = https://xxxxx/pir AuthenticationToken = AAAA pirPrivacyProxyFailOpen = NO pirSkipRegistration = NO } } But I got this error when I tried to enable the service on the app: Received filter status change: <FilterStatus: 'stopped' errorMessage: 'The operation couldn’t be completed. (NetworkExtension.NEURLFilterManager.Error error 9.)'> What does that error mean? And how to fix it?

I am developing an iOS App for a Bluetooth peripheral using SwiftUI with Swift 5 or 6. I have a few past attempts that got so far (connected to a peripheral), and some downloaded examples that connect to peripherals. Lately (last month or so), my current attempt never gets BleManager to start, and every attempt ends at my View that says 'please enable Bluetooth'. The Xcode console is totally blank with no print outputs. Coding Assistant suggested the init() in my @main structure could contain print("App initializing"), but even that never prints. Coding Assistant suggests: "• Open your project's Info.plist in Xcode. • Make sure UIApplicationSceneManifest is present and configured for SwiftUI, not referencing any storyboard. • Ensure UIMainStoryboardFile is not present (or blank)." but there is no info.plist because it is no longer required. Downloaded sample code runs and connects to peripherals, so Bluetooth is working on my iPhone and the Bluetooth device is accessible. My older attempts used to work, but now have the same problem. All attempts have "Enable Bluetooth to connect to Device" in the Privacy - Bluetooth Info.plist setting. Something is fundamentally wrong with many different code attempts. I have searched all the various settings for mention of SwiftUI or Storyboard, but not found them in working or failing projects. The downloaded code which works has minimum deployment iOS 14.0 and Swift Compiler Language Version Swift 5. My latest code attempt has minimum deployment iOS 16 and Swift 5. All code is target device iPhone (I am testing on iPhone 16e running iOS 26.2.1) and developing with Xcode 26.2 on MacBook Air M1 running the latest Tahoe. I do a Clean Build Folder before every test, and have tried re-starting both Mac and iPhone. How can my coding fail so spectacularly?

The documentation specifies that when Contacts framework returns unified contacts that each fetched unified contact object (CNContact) has its own unique identifier that’s different from any individual contact’s identifier in the set of linked contacts and that when refetching a unified contact, that this identifier should be used. There is also an analogous identifier within the list of contactRelations, but each of these don't seem to corespondent to the unified contacts. For example, is a new contact (Sheryl Zakroff) is created in the simulator Contacts and their spouse is set to Hank Zakroff. However, the GUID created for the contactRelations identifier does not correlate to the original Hank Zakroff GUID and cannot be searched. Is this a bug or what is the indent of the contactRelations identifier? Here's a debug output of walking the unifiedContacts: Name: Hank Zakroff 2E73EE73-C03F-4D5F-B1E8-44E85A70F170 - Other : (555) 766-4823 - Other : (707) 555-1854 Name: David Taylor E94CD15C-7964-4A9B-8AC4-10D7CFB791FD - Other : 555-610-6679 Name: Sheryl Zakroff DE783BC8-7917-4138-93F6-3AF0FD4CE083 - Other : (707) 555-1854 - Spouse: <CNContactRelation: 0x60000000dd60: name=Hank M. Zakroff> - 534B467D-CA00-46D3-897C-16EEA782C9CF - Looking for ["534B467D-CA00-46D3-897C-16EEA782C9CF"] []

I'll try to ask a question that makes sense this time :) . I'm using the following method on NSFileManager: (BOOL) getRelationship:(NSURLRelationship *) outRelationship ofDirectoryAtURL:(NSURL *) directoryURL toItemAtURL:(NSURL *) otherURL error:(NSError * *) error; Sets 'outRelationship' to NSURLRelationshipContains if the directory at 'directoryURL' directly or indirectly contains the item at 'otherURL', meaning 'directoryURL' is found while enumerating parent URLs starting from 'otherURL'. Sets 'outRelationship' to NSURLRelationshipSame if 'directoryURL' and 'otherURL' locate the same item, meaning they have the same NSURLFileResourceIdentifierKey value. If 'directoryURL' is not a directory, or does not contain 'otherURL' and they do not locate the same file, then sets 'outRelationship' to NSURLRelationshipOther. If an error occurs, returns NO and sets 'error'. So this method falsely returns NSURLRelationshipSame for different directories. One is empty, one is not. Really weird behavior. Two file path urls pointing to two different file paths have the same NSURLFileResourceIdentifierKey? Could it be related to https://developer.apple.com/forums/thread/813641 ? One url in the check lived at the same file path as the other url at one time (but no longer does). No symlinks or anything going on. Just plain directory urls. And YES calling -removeCachedResourceValueForKey: with NSURLFileResourceIdentifierKey causes proper result of NSURLRelationshipOther to be returned. And I'm doing the check on a background queue.

With the same firmware, OTA testing on the DCL test network was successful in September 2025, and the Home app was able to deliver software update notifications. Since the beginning of 2026, however, the Home app no longer delivers software update notifications. This is bug number: FB21922369

When printing image/photo files via AirPrint, selected finishing options (e.g., Punch) are not applied unless a preset is chosen. reproduction steps: Select an image on iOS Tap Print → choose printer/server Set Finishing Options → Punch Print Observed: Finishing options not applied IPP trace shows no finisher attributes in the request working scenario: Select any Preset (e.g., Color) before printing Finishing options are then included in IPP and applied Note: Issue does not occur when printing PDFs from iOS; finisher attributes are sent correctly. Is this expected AirPrint behavior for image jobs, or could this be a bug in how iOS constructs the IPP request for photos?

Hi everyone, We are currently exploring ways to implement a frictionless Wi-Fi setup for our hardware devices without requiring a dedicated third-party application. We are interested in leveraging Apple's WAC (Wireless Accessory Configuration) to sync Wi-Fi credentials directly from iOS devices. However, we have struggled to find comprehensive technical documentation or specifications regarding the WAC service. Could anyone point us to the official source for these materials? Additionally, we have a couple of technical questions: 1.We are testing WAC provisioning and found that the Home app can discover our device and successfully get it online. However, it always ends with a "Failed to add accessory" message. Does WAC support imply that a device should be addable via the Home app? If not, why is the Home app able to discover and start the setup for a non-HomeKit WAC device? 2. Our device is already Apple AirPlay certified. Does implementing WAC require additional standalone certification, or is it covered under the existing MFi/AirPlay certification umbrella? Any insights or guidance would be greatly appreciated. Thank you!

Hello. We are facing very silent and hardly replicable issue. All UserDefaults.standard data the application saved and was using to determine the state of app is lost and app behaves as if it was freshly installed. The issue always occurs only if we leave app on background for long time or if we manually swipe the app from the background apps. In case we swipe, this issue can occur in minutes, hours or up to 2 days by our latest testing. One important factor is that the app was developed using iOS18 in which issue never occured. Next it was being tested on iOS26 and it did everytime. Any currently available version of iOS26 reported this issue, all the way up to 26.2.1 (23C71). Our application is going through major upgrade of its whole lifecycle and services so it is possible this issue is caused by a bug in development as the production version does not report this issue neither on iOS26 of any version. The following list contains how we tried to fix this issue but none of which helped. App prewarming in the background (postpone all initialization including searching UserDefaults.standard for when isProtectedDataAvailable) Calling UserDefaults.standard.synchronize() everytime after saving data despite it is not recomended Built app using different SDK's (tested on iOS18 and iOS26 SDK) Distributed the app from local machine aswell as on TestFlight itself We searched through currently opened and closed issues for third-party libraries app uses regarding 'iOS26' and 'UserDefaults', especially those who were added recently with no success. The structure using which we save data into UserDefaults.standard did not change, we have only added few more settings to save through the lifecycle of the app after update. We estimate the overall increase is merely 30% more of what it used to be in previous version. Any ideas are much appreciated. We are considering to use different or fully custom ways to store app's settings.

Description I am seeing a consistent crash in a NEDNSProxyProvider on iOS when migrating from completion handlers to the new Swift Concurrency async/await variants of readDatagrams() and writeDatagrams() on NEAppProxyUDPFlow. The crash occurs inside the Swift Concurrency runtime during task resumption. Specifically, it seems the Task attempts to return to the flow’s internal serial executor (NEFlow queue) after a suspension point, but fails if the flow was invalidated or deallocated by the kernel while the task was suspended. Error Signature Thread 4: EXC_BAD_ACCESS (code=1, address=0x28) Thread 4 Queue : NEFlow queue (serial) #0 0x000000018fe919cc in swift::AsyncTask::flagAsAndEnqueueOnExecutor () #9 0x00000001ee25c3b8 in _pthread_wqthread () Steps The crash is highly timing-dependent. To reproduce it reliably: Use an iOS device with Developer Settings enabled. Go to Developer > Network Link Conditioner -> High Latency DNS. Intercept a DNS query and perform a DoH (DNS-over-HTTPS) request using URLSession. The first few network requests should trigger the crash Minimum Working Example (MWE) class DNSProxyProvider: NEDNSProxyProvider { override func handleNewFlow(_ flow: NEAppProxyFlow) -> Bool { guard let udpFlow = flow as? NEAppProxyUDPFlow else { return false } Task(priority: .userInitiated) { await handleUDPFlow(udpFlow) } return true } func handleUDPFlow(_ flow: NEAppProxyUDPFlow) async { do { try await flow.open(withLocalFlowEndpoint: nil) while !Task.isCancelled { // Suspension point 1: Waiting for datagrams let (flowData, error) = await flow.readDatagrams() if let error { throw error } guard let flowData, !flowData.isEmpty else { return } var responses: [(Data, Network.NWEndpoint)] = [] for (data, endpoint) in flowData { // Suspension point 2: External DoH resolution let response = try await resolveViaDoH(data) responses.append((response, endpoint)) } // Suspension point 3: Writing back to the flow // Extension will crash here on task resumption try await flow.writeDatagrams(responses) } } catch { flow.closeReadWithError(error) flow.closeWriteWithError(error) } } private func handleFlowData(_ packet: Data, endpoint: Network.NWEndpoint, using parameters: NWParameters) async throws -> Data { let url = URL(string: "https://dns.google/dns-query")! var request = URLRequest(url: url) request.httpMethod = "POST" request.httpBody = packet request.setValue("application/dns-message", forHTTPHeaderField: "Content-Type") let (data, _) = try await URLSession.shared.data(for: request) return data } } Crash Details & Analysis The disassembly at the crash point indicates a null dereference of an internal executor pointer (Voucher context): ldr x20, [TPIDRRO_EL0 + 0x340] ldr x0, [x20, #0x28] // x20 is NULL/0x0 here, resulting in address 0x28 It appears that NEAppProxyUDPFlow’s async methods bind the Task to a specific internal executor. When the kernel reclaims the flow memory, the pointer in x20 becomes invalid. Because the Swift runtime is unaware that the NEFlow queue executor has vanished, it attempts to resume on non-existing flow and then crashes. Checking !Task.isCancelled does not prevent this, as the crash happens during the transition into the task body before the cancellation check can even run. Questions Is this a known issue of the NetworkExtension async bridge? Why does Task.isCancelled not reflect the deallocation of the underlying NEAppProxyFlow? Is the only safe workaround? Please feel free to correct me if I misunderstood anything here. I'll be happy to hear any insights or suggestions :) Thank you!

I am implementing BLE scanning and connection using CoreBluetooth in a Flutter application with native iOS Swift code. BLE scanning and connection work correctly in the foreground and for a short time after the app is sent to the background. However, after some time in the background, BLE scanning stops and the device is no longer discovered. The app appears to be suspended by iOS. Key Observation: When location services are actively in use (navigation arrow visible in the iOS status bar), BLE scanning and reconnection work reliably in the background. When location services are not actively running, BLE scanning stops in the background even though the app has “Always Allow” location permission. Expected Result BLE scanning and connection should continue to function in the background using the Bluetooth LE background mode, without relying on active location updates. Actual Result BLE scanning starts successfully App enters background After some time, scanning stops Device is no longer discovered BLE works again only if location services are actively running BLE Connection Behavior One-time scan connects successfully to a BLE medical device App is sent to background Existing connection does not disconnect However, new scans or reconnections fail once the app is suspended Relevant Native iOS Code (AppDelegate) import Flutter import UIKit import CoreBluetooth @main @objc class AppDelegate: FlutterAppDelegate { private var backgroundTaskID: UIBackgroundTaskIdentifier = .invalid override func application( _ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? ) -> Bool { GeneratedPluginRegistrant.register(with: self) if let identifiers = launchOptions?[UIApplication.LaunchOptionsKey.bluetoothCentrals] as? [String] { print("App relaunched for BLE state restoration: \(identifiers)") } NotificationCenter.default.addObserver( self, selector: #selector(appDidEnterBackground), name: UIApplication.didEnterBackgroundNotification, object: nil ) return super.application(application, didFinishLaunchingWithOptions: launchOptions) } @objc private func appDidEnterBackground() { backgroundTaskID = UIApplication.shared.beginBackgroundTask { self.endBackgroundTask() } } private func endBackgroundTask() { if backgroundTaskID != .invalid { UIApplication.shared.endBackgroundTask(backgroundTaskID) backgroundTaskID = .invalid } } } Questions for DTS: Is it expected behavior that CoreBluetooth background scanning effectively stops once the app is suspended, even when the Bluetooth LE background mode is enabled? Why does BLE background scanning appear to work reliably only when location services are actively running? Is iOS internally associating BLE background execution with active location updates? For continuous BLE reconnection (medical device use case), is the recommended approach to rely solely on CoreBluetooth state restoration instead of continuous background scanning? Is it considered best practice to avoid long-running BLE scans in the background and instead wait for system-delivered BLE events? Additional Notes Issue is reproducible on real devices Not using private APIs or unsupported background execution methods Objective is to follow Apple-recommended, App Store–compliant behavior

This is a copy of a reply to this post. https://developer.apple.com/forums/thread/722222?page=1 I'm posting as new in the hope someone might have more up-to-date information, as I'm pulling out what little hair I have left. I'm using Storekit 2, testing in Xcode with a local Storekit config file. I have created a very minimal system to investigate this issue. I have a SwiftUI-based window using SubscriptionStoreView, and my app set up with the usual listener. I have four types of auto renewing subscription, configured in the local Storekit config file. With my app running, I subscribe to the lowest-level subscription I offer, via the SubscriptionStoreView. Notification of the inital purchase arrives, but subsequent auto-renewals do not trigger any action in my listener for Transaction.updates. They arrive as expected in the Transaction Manager. Radio silence in my listener. If I upgrade one subscription (via my SubscriptionStoreView) I see this reflected in the UI immediately, and also in the Transaction Manager, but the update that arrives in Transaction.updates refers to the old subscription, and has the isUpgraded flag set to false. Also, can anyone remind me what the grey warning triangle next to entries in the Transaction Manager means. I'm assuming it means unfinished, as that's what the sidebar indicates. Can the testing system really be this broken, or am I wildly off the mark? Unless I'm doing something fundamentally wrong this all seems extremely flakey, but happy to be proved wrong. I find this all rather unsettling if I can't test reliably, and am concerned that I my app may end up in this situation if I use storekit 2: https://stackoverflow.com/questions/73530849/storekit-renewal-transactions-missing-in-transaction-all-or-transaction-updates

Do we need to take approval for any entitlement for the extension Unwanted Communication because currently I do not see my app in the Settings under SMS/Call Reporting extensions.

My iOS application needs to connect a device by wifi and exchange data between them. The way of transmission is using the UDP protocol, most of all, it works well. But some part of iOS devices will loss the package always. Even if re-open the application or reboot wifi devices, or reboot iOS devices, it can not be solved. Only reset the network settings on iOS devices could fix it. But this can not make sure that be well always, if occurs in the future. User need to reset network setting again. Are there any brothers know or meet this phenomenon? Thanks for your time to research this.