I would guess there is likely an issue where for some reason the game cannot connect to our servers (possibly because of being blocked by a firewall or other similar program).
For anyone who's having this problem, if you can put OOTP into debug mode and post the resulting file in the bug reports forum, we can check that out. This might provide a little more info as to why this is happening and suggest a potential solution.
https://support.ootpdevelopments.com...debug-log-file