I have an iPhone 5 which I purchased (from India) in Nov 2012 and now it is out of warranty. I found an old SIM Card, which I purchased from Singapore when I was visiting that country, and put it inside my phone just to check if it still works or not.
I asked my friends to call me on that number, they could hear the phone ringing tone but my phone was not ringing so after that I switched back to my local SIM which was working before.
Now I am unable to make any calls from my number, all outgoing calls fail immediately with a "Call Failed" message and I can hear 2 beeps. I can receive Incoming calls, send and receive texts and can browse the internet using 3G data connection on the same SIM.
I tried the my local SIM in other phone and it works perfectly fine which confirms that there's no issue with the service provider.
I Tried some other local SIM in my iPhone 5, that doesn't work either.
This is definitely some issue with my iPhone 5. What could the issue be?
I am really worried because it is out of warranty now.
Best Answer
Another solution I found to this problem:
Open
Settings -> Phone -> Show Caller IDIt'll take some seconds to load the and show a loading indicator, after that is done the phone will be able to make and receive calls