iPhone 4s cannot make outgoing calls
My iPhone 4S using iOS 7.0.4, started having the problem cannont make outgoing calls. During the same time I can get incoming calls, can send and receive sms-es, and browser the internet.
After quite a lot of work, figured out that just going to "Settings > Phone > Show My Caller ID" fixed the problem temporarily. But once I restarts the phone or while travelling reaches a next city with a break in the mobile network again the same happens.
Any idea how to fix this problem permanently?
iPhone 4S, iOS 7.0.4