iPhone 12 can’t speak on phone calls

i had exactly the same. Have now returned phone to it's factory settings snd started again snd it's all fine.

Try resetting Network settings. One of our doctors texted me for support and it worked after i had him do this.

No it’s not AirPod related(at least for me)

I downgrade the data setting to 4G and everything works fine now.

(like just from phone setting )

The problem of not being able to hear incoming calls on the IPhone 12 is actually a fault with the phone. Apple are apparently aware of the issue and are working on an update to resolve it. However in the meantime there is a simple solution that works! Go into Settings, General, Reset, Reset Network Settings. Enter your PIN and rest this. You will NOT lose anything on your phone and once done will resolve the issue of not being able to hear incoming calls. It worked for me immediately and i haven’t had a problem since

I use an iPhone 12 which I purchased in Jan 2021. Sometimes when I make phone calls the other people can’t hear me... but on rebooting it works fine...Not thinking it would be an issue with the microphone

I did what John Barrie suggested above:

“I solved it by turning off the Phone Noise Cancellation tab (Settings, Accessibility, Audio/Visual, Phone Noise Cancellation). “

That seems to work but I also don’t go on speakerphone anymore. Hope that helps you.

I went to apple authorized technician and he checked it out and said it was my services provider at fault!

Before that I had an apple technician check it out and he said the same thing but also said it could be the Sim card.

My provider is Koodo so I’m going back to them again and see what happens!

Apple is aware of the issues (especially the audio quality ones), and they are actually fixing phones (all of the iPhone 12 line except the pro max at the moment). There is something else occurring as well software wise that is hopefully going to be fixed with the release of iOS15. I will say my strongest suggestion is to call apple support as you need, as often as you need, jump through the hoops as they ask, make notes when things go wrong again and continue to build a case file(s). They are tracking it. I have been fighting this since December, and hopefully will have made actual progress this past week and a half. It has been frustrating. I wish you the best of luck!!!!

I do “volume up volume down and hold lock button until I see apple logo” then it works for a while :/ it’s frustrating

Worked for me too! Factory reset and no problems since!

I had this issue with my new iPhone 12 Mini. I solved it by turning off the Phone Noise Cancellation tab (Settings, Accessibility, Audio/Visual, Phone Noise Cancellation). Hope this helps.

I've had the exact same issue on my iPhone 12 Pro. On both in coming and out going calls, I can hear the other person clearly and they can't hear me at all. I've had to restart my phone every time for it to work again.

My suspicion is that it's related to Bluetooth, even though no device is actively connected when the issue occurs, it is on days that I've been using my AirPod Pros a lot and have been switching between devices.

Just wanted to let you a know that I'm having the same issue and it's a defective speaker. If it is a 12 you need to make an appointment to the genius bar to get it fixed. I tried to go to Best buy through apple and the phone was too new for them to fix it.

I’ve followed all recommendations from the link you provided and the conclusion is that the microphone is working fine. I’ve also tested front and rear facing cameras and the audio is fine on those as well.

As everyone on this thread has stated, the microphone only stops working on certain phone calls, at which point a reboot consistently resolves the issue.

Doesn’t that suggest a software issue?

Hard to say for sure. As your issue is intermittent, it can just be that it never happened when you did your tests.

Another thing to note is that it can even be on the carrier side if it only happens on phone calls.

To rule out a software issue on your end you can try a clean install. backup, factory reset via a computer, and set up as new.