Failing Microphone in iPhone 7 No app requiring microphone works on my iPhone 7, including calls. Strange thing is that calls fail with call fail message, not just have bad connections or other end complaining about not being able to hear. Other apps also refuse to work. For example ‘Voice notes’ state ‘no audio devices found’.
You can try Phone diagnostics (https://apps.apple.com/us/app/phone-diagnostics/id1171677218) to check all microphones on your iPhone.