Xbox live is having issues right now, it's probably related to that. I can't play either.
You CAN get on if you are persistent, but there definitely is something going on. I was on earlier with no problems, then I signed out and shut down for lunch. Logged back in and noticed that my Dashboard color scheme was not my custom colors. Then I realized that I wasn't signed in to XBL, which should be automatic. Signed in, and things looked normal, but when I launched ELITE, I was asked to confirm which account (GT) to use for the game. (Not normal), and my icon was grayed out.
Tried to launch ED, but it just sat there, and I ended up with a gray screen and a perpetual progress spinner. Backed out to the dashboard and QUIT the game. Tried a full power down/ restart of the console, but it came back up and didn't automatically sign in.
This went on for about 5 times in a row. All my network tests showed normal and GOOD TO GO. On my 5th attempt, I was able to log in to XBL and fully load ED, and I have been on the game in SOLO mode ever since. About 3 hours now.
So... If you manage to log in to XBL and get a good connection, and get into the game .... DON'T LOG OUT! If you plan on playing today and tonight, best to just stay logged in to ED and XBL once you are able to.
If you sign out of both, you may not be able to sign back in later.