I assume your using the correct sim as you didn't have problems with the upgrade(no request for activation )
Try taking out the sim card, wiping and replace... or try resetting all settings in Settings>General>Reset>Reset All Settings
I assume your using the correct sim as you didn't have problems with the upgrade(no request for activation )
Try taking out the sim card, wiping and replace... or try resetting all settings in Settings>General>Reset>Reset All Settings