Can receive but cannot make outgoing calls on an iPhone 5S My iPhone 5s which I bought a year ago shows "Call Failed" whenever I hit "send", it doesn't matter which number I'm dialing. I can get incoming calls, FaceTime calls, messages, and apps are working fine. I placed my SIM in another device and mananged to make calls, and I tried putting another SIM in my iPhone, and once again got the instant "Call Failed" message.

Is this more likely to be a software problem or hardware? How can this be addressed?
This happened in my iPhone 4S since one of iOS 7 updates, sent many messages on Apple's contact form, no answer and no fix to date with the latest iOS 8.3, I temporary fix it by dialing *#31#.

It shows a message "Setting Interrogation Succeeded, Calling Line ID Restriction Disabled" and then can call normally.