Just bought an Iphone 4S this evening, and I can't seem to make a phone call. I dial the number, and it said call ended right away. Anyone know why this is? I tried the whole way home, so its not that there was no service or anything.
Another thing to try (although 9/10 times in my experience Dennis' suggestion works). Go to settings, general, reset, and then choose reset network settings. This won't delete anything except for the wifi networks you are connected to.