Common Causes of iPhone Microphone Not Working
Microphone is Blocked/Obstructed
The microphone ports are also one of the most common causes why the iPhone mic is not working, if that is blocked, covered and clogged. This might occur if the microphone is blocked by the case or screen protector, after that may be there is dust and debris buildup in your Microphone openings. Fortunately, the solution is simple: just take off any case that you have on or screen protector and gently rub the microphone opening with a thin tooth brush or simply blow in it ( a can of compressed air would work great for this ).
Outdated iOS Version
Having an outdated iOS on your iPhone can result in microphone issues. Make sure your iPhone is updated to the latest iOS version by going to Settings >
General > Software Update If there is an update, just install it to check if the problem still persists.
Bluetooth or App-Related Issues
From time to time the microphone will not function because of Bluetooth or app issues, For the iPhone users, they should possible check if the Bluetooth headphones or speakers linked with their kit are disconnected and afterwards affirm whether it is your microphone that now eventually works. Also, make sure the app you are using has microphone permission: Settings > Privacy > Microphone. Ensure that the app is turned on and has the access to use microphone.iPhone microphone not working (ad)
Hardware Failure
The microphone does not work in these circumstances because it is physically dead. If it still does not work after performing the above steps, then its quite possible that there is an issue with the microphone hardware. If so, you will have to call the Apple Support or go down to the Apple Store.