Answer to "Microphone not working when making/receiving calls"Iphone 5S. Software version 11.1.1 Front Microphone while call - Not working Speaker while call - Working Speaker while Music - Not working Headphone - Working in all condition Seems phone stuck in 'Headphone' mode. There is no setting in any setting to comeout from this situation. Tried setting > Airplane mode > On.. Leave phone for couple of min and turn Airplane mode Off. Surprise. It started working.. I am not sure what happen.. Seems It's iOs 11 problem.