Why won't my phone ring when calls are incoming (HTC ONE X)?

[AC Question]

My phone won't ring when calls are incoming it's a HTC ONE X

I accidentally put my HTC ONE X into "Areoplane" Mode. I didn't realise what I'd done, but when I put the phone back into what I shall call it's ordinary mode. Now I can't get the phone to ring for incoming calls. If you can help please help me.

 

[B. Diddy]

Re: My phone won't ring when calls are incoming it's a HTC ONE X

Welcome to Android Central! It's not in Mute mode, correct? Does it persist after a reboot?