Hi everyone,
We’re seeing a rare but frustrating issue in our iOS VoIP app and would appreciate any advice.
What’s happening:
In some VoIP calls between two users (let’s say A and B), B can’t hear A’s voice, but A can still hear B just fine.
It doesn’t happen often, but once it does, the issue persists until the device is restarted.
Users who experience this issue typically have other voice or conferencing apps installed and actively use them.
They report that when our app runs into this problem, those other apps continue to work normally.
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What we’ve ruled out:
• AVAudioSession has microphone permission, and audio input works under normal conditions
• Network conditions are stable
• App-side logic seems solid — the issue occurs extremely rarely (e.g., 1 out of several thousand calls), making it unlikely to be caused by a consistent bug in our call flow
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What we’ve tried to fix it (all ineffective):
Restarting the call — no effect
Force-quitting and relaunching the app — no effect
Toggling Bluetooth: disconnecting and reconnecting audio route, or switching back to built-in mic — no effect
Replugging wired headphones or switching to the default iPhone audio input — no effect
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What actually works (so far):
• Restarting the device — this is the only action that reliably fixes the issue
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What we’re looking for help with:
1. Does this sound like an iOS-level AVAudioSession routing or audio stack issue?
2. Is there any way to recover from this state without rebooting the device — either through iOS system settings or programmatically?
3. Are there any known audio routing or input bugs in iOS that match this behavior?
Thanks in advance — any suggestions or pointers would be greatly appreciated!
