For those experiencing issues joining games and receiving errors 660 or 667. This is a known bug that is caused by certain games becoming un-joinable.
This issue is also the cause of the issues when looking for games through the games list as the un-joinable games are clogging up the list and causing it to refresh constantly.
To get around this until the issue is solved, it is best to use the auto match function, as this gets around the issue.
We understand this is not ideal, we are working to fix this issue as fast as we can. Keep an eye on this post for updates.
We are sorry for the inconvenience.
Update: The fix for these issues is now released!
The fix is now released for both platforms. Remember to update. Enjoy!