My fiancee's X1 had a problem with connected drive, wasn't working for about 3 months. The dealership couldn't fix it, the idiots on the 1800 number couldn't fix it, reinstalling the app and refreshing connected drive from the car didn't fix it.. but.. I got it working by doing the following:
Go to:
http://connecteddrive.bmwusa.com
Log in with your BMW credentials, you will see your car on the main page
There will be a little check box where it says "Remote Services are active."
Uncheck the box
Wait about 5 mins and recheck the box
I think this might re-register it with the servers or something, but whatever it does her X1 is responding again after almost 3 months of no connectivity.