Chosen Solution
I have a problem with my iPhone 6S : Callers can’t hear me when I make or receive a call, although the lower mic is definitely functioning for other things such as Voice Mail, Siri, etc.. What they do hear is either with dropouts, muffled or nothing. This seems to be a software, not hardware problem. But no amount of rebooting, resetting, etc. solves the problem Does anyone have a solution?
Have you tried disabling voice cancellation. Which is under general > accessibility > voice cancellation.
