Since yesterday I’ve been unable to make calls with my iPhone. As soon as I dial any number, I get CALL ENDED followed immediately by CALL FAILED. I’m able to receive calls and send SMS, though.
I completely restored my iPhone, made sure the time zone & caller ID are correct as suggested in Apple’s support forums, and even reset network settings and the problem still persists. If nothing else works, I’ll probably be taking a trip to the Apple store.