There appears to be an issue with WP8 today (26-11-12). Doesn't appear to be only Nokia 920 from what I've read in other forums and is definitely not carrier specific (posted in the US, UK and Germany on different carriers.
The issue appears to have started (or at least, was first noticed) when trying to send texts, which didn't appear to go. Even last week, people were noticing that they had to resend texts on the odd occasion.
Since then, the issues appears to have got more serious and some of us have begun to lose the ability to send emails too or use any of the WP8 Hubs (music, people, messaging, etc). Microsoft aware so please if you are experiencing this, post here and also with Microsoft at: Text Message "Can't Send" in WP8 - Microsoft Community where a thread has already started. They are asking for users to provide information about their network / handset in order to come up with a solution.
The issue appears to have started (or at least, was first noticed) when trying to send texts, which didn't appear to go. Even last week, people were noticing that they had to resend texts on the odd occasion.
Since then, the issues appears to have got more serious and some of us have begun to lose the ability to send emails too or use any of the WP8 Hubs (music, people, messaging, etc). Microsoft aware so please if you are experiencing this, post here and also with Microsoft at: Text Message "Can't Send" in WP8 - Microsoft Community where a thread has already started. They are asking for users to provide information about their network / handset in order to come up with a solution.