VOIP application message notification sound during call

We are developing VOIP application. Which includes message and call features

During call if our app receives a message. Message notification sound is not played in iOS 13 and iOS 14.

When we check same issue with Whatsapp message notification sound is played in iOS 14. But in iOS 13 message notification sound is not played.

We are setting mode and category like below

AVAudioSession.SharedInstance().SetMode(AVAudioSession.ModeVoiceChat, out err);

AVAudioSession.SharedInstance().SetCategory(AVAudioSessionCategory.PlayAndRecord, AVAudioSessionCategoryOptions.AllowBluetooth | AVAudioSessionCategoryOptions.AllowBluetoothA2DP);

Please let me know if any solution available to play notification sound during on going call.

VOIP application message notification sound during call
 
 
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