I was a having this issue a few times ultra early in the AM when the wife was trying to play some games. She'd click on a game, it'd get that error; then pass me the controller and every other game I tried to launch would work fine, pass the controller back to her, it would get an error. This happened a few times In a row, kind of funny to be honest. It eventually worked after her third time around.
I would suggest you try launching different games, then go back to the one your are actually trying to play. Maybe offline mode? I didn't try that.
Download speeds were also a bit wonky this morning... it was DLing at like 50mbps, then 60, then 220 for a bit (which is what it normally downloads at), then down to 80 and my download finished up at around 180mbps/