File sharing by share extension works on simulator but fails on device

I developed an app with a share extension, and want to receive files shared from other apps by the share extension.

The following is what I do in the share extension.

let attachments = (self.extensionContext?.inputItems.first as? NSExtensionItem)?.attachments ?? []

guard #available(iOSApplicationExtension 14.0, *) else {return}

let contentType = "public.file-url"

for provider in attachments {

    guard provider.hasItemConformingToTypeIdentifier(contentType) else { continue }

    provider.loadItem(forTypeIdentifier: contentType, options: nil) { [unowned self] (data, error) in

        let fileUrl = data as! URL





        // Get shared file data here,

        // works fine on simulator, but the permission error occurs if run on device

        try? Data(contentsOf: fileUrl)

    }
}

self.extensionContext?.completeRequest(returningItems: [], completionHandler: nil)

.

It works fine on simulator, but get an error like below if I read the shared data (using Data(contentsOf: url)) when runs on device.

.

Failed to read file, error Error Domain=NSCocoaErrorDomain Code=257 "The file “[File name]” couldn’t be opened because you don’t have permission to view it." UserInfo={NSFilePath=/private/var/mobile/Containers/Shared/AppGroup/[some ID String]/File Provider Storage/[File name], NSUnderlyingError=0x2800b42a0 {Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"}}

I am running this code on an iPhone 12, iOS 15.3.1. Xcode 13.4.1.

If any further information is needed, please let me know.

Thank you.