Voice memos won't play either
I have this problem too, I recorded a bunch of ideas I had for lyrics and melodies to write new songs, now I can't access them :(
iPhone X, iOS 14
With the limited information provided by you, I have made a few guesses, and here is my answer.
You may try the following options
- Settings > Voice Memo > Audio Quality > [ Try whichever works ]
- Was it your last recording then, test your microphone on your iPhone, If the microphones on your iPhone, aren't
- use iMovie to test your recording and recording sound level
- Upload to iCloud / iCloud Drive then try playing
- Convert the m4a audio file to .wav or aac audio file using any audio converter (Many available in the app store)
- Last resort; download to Mac/PC use any Audio repair tools available over the internet. (Warning; Risk is yours)