This could very well be an issue with the actual ringtone file, are you using a purchased ringtone or a default ringtone? Otherwise, it sounds like a software issue (as a hardware issue would rarely be intermittnet). I recommend restarting, resetting, and restoring if necessary.
Matt, thanks so much for your answer. I restarted my phone. Shortly afterwards, it chimed that I had a new voicemail, without ringing. 5 minutes later, while I was sitting in the same chair (so I don't think it's a reception issue) it rang from a different caller. I have no custom ringtones. I hesitate to reset (doesn't that restore to factory-everything?) because my hard drive is limping along, and I'm afraid it will die while restoring. If you have any other ideas, I'd love to know about them. Thanks!
That means your iPhone is in "Do Not Disturb" mode which will cause you to not be alerted when you get a notification (such as a phone call, message, Facebook/twitter notification).
To turn this on or off, go to:
Settings < Do Not Disturb < "ON" or "OFF"
You can also edit the times you want "Do Not Disturb" to be on by going to
Settings < Notifications < Do Not Disturb
Hope this helps
My iPhone doesn't ring either. I've been doing my own investigating and I've fond a few other people w the same issue. Someone calls and the call goes directly to a voice mail. They call a 2nd time immediately after and the phone will ring. All of this started after the new upgrade.
Hi im having troubles with my iphone. When i call or recieve a call i cannot hear or them hearing me unless its on earphones or on speaker. how can i fix this problem without taking it to a store?