I have been trying to join into my realm, and it has consistently not allowed me to. The game will switch to the realm loading screen and show "joining realm, this may take a few moments" for several minutes, then go back to the menus and show an error message. How can I join my realm? I've tried restoring it to a backup, and that had no effect.

I was able to load it just fine earlier this afternoon, but one of my friends had trouble last night. For some reason, now neither of us can get in. One of my other friends has been having the same problem with his realm for several weeks now.