We have an app store app that hosts an internal webserver we use as a proxy and it works for a period until iOS 18.3.x decides our cert is no longer valid at which point our customer have reinstall the app. This has only become a problem on iOS18.3. We publish the self-signed with out app, and it is valid and accepted until it's not. We know the cert is valid and our implementation of the local proxy has not changed. If we install a cert on the device and trust it, then the app will start behaving normally again without reinstall. We have replicated this locally and the error we are seeing is:
Error Domain=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made." UserInfo={NSLocalizedRecoverySuggestion=Would you like to connect to the server anyway?, _WKRecoveryAttempterErrorKey=<WKReloadFrameErrorRecoveryAttempter: 0x301111e40>, networkTaskDescription=LocalDataTask <541390E2-65FA-47AB-80B1-10209D6C761A>.<3>, _kCFStreamErrorDomainKey=3, NSErrorPeerCertificateChainKey=( "<cert(0x108e3b700) s: 127.0.0.1 i: 127.0.0.1>", "<cert(0x108e3b980) s: 127.0.0.1 i: 127.0.0.1>" ), NSErrorClientCertificateStateKey=0, NSErrorFailingURLKey=https://localhost:8082/Blablal/?device=ios&sftouch=1&pgport=8081&secure=1, NSErrorFailingURLStringKey=https://localhost:8082/blahblah/?device=ios&sftouch=1&pgport=8081&secure=1, NSUnderlyingError=0x301e1d680 {Error Domain=kCFErrorDomainCFNetwork Code=-1200 "(null)" UserInfo={_kCFStreamPropertySSLClientCertificateState=0, _kCFNetworkCFStreamSSLErrorOriginalValue=-9802, _kCFStreamErrorDomainKey=3, _kCFStreamErrorCodeKey=-9802}}, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <541390E2-65FA-47AB-80B1-10209D6C761A>.<3>" ), _kCFStreamErrorCodeKey=-9802, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <541390E2-65FA-47AB-80B1-10209D6C761A>.<3>, networkTaskMetricsPrivacyStance=NotEligible, NSURLErrorFailingURLPeerTrustErrorKey=<SecTrustRef: 0x302670a50>, NSLocalizedDescription=An SSL error has occurred and a secure connection to the server cannot be made.}