I decided to try Stadia just now. Their games page has lots of games saying "try for free X minutes", so I tried picking one. Selected the Google account to use

I decided to try Stadia just now. Their games page has lots of games saying "try for free X minutes", so I tried picking one. Selected the Google account to use, and then I get a 403. Tried a different game with a different Google account. Also 403.