Is this happening when you are using your phone mic or the headset's mic?
1. If it's the phone mic, then diagnose it using this app itself. In Members app main page bottom menu > Get Help > Diagnostics > Start > Mic
2. Force restart the phone and check.
3. Clear the cache partition and check.
4. Try starting the phone in safe mode and check. If it works in safe mode, a third party app might be causing the issue.
Check the recent apps you have installed, any background apps running at the moment when you are in the call and check if they are having microphone access. Disable if you have apps like that and recheck.
