AirPods: Microphone Does not Work on phone calls but works using apps

For the last few days, no one is able to hear me on the phone when I use my Air Pods (2nd Gen). I thought perhaps the mic is damaged however, I can record myself using the Voice Recorder app using the AirPods.

I have unpaired my AirPods and paired them again but the issue still persists.

Any ideas what could be wrong?