I have a similar problem with linphone-sdk and CallKit.
And the problem in my case was missing audio key in Info.plist.
You need to have these keys, if you want you app works with AudioSession in background mode.
<key>UIBackgroundModes</key>
<array>
<string>voip</string>
<string>audio</string>
</array>
I have a similar problem with linphone-sdk and CallKit.
And the problem in my case was a missing audio key in Info.plist.
You need to have these keys, if you want you app works with AVAudioSession in background mode.
<key>UIBackgroundModes</key>
<array>
<string>voip</string>
<string>audio</string>
</array>