if creating game doesn't work, but joining works => change gs (stuck gs will get restarted eventually by watchdog)
if you can't both create/join a game (and changing gs doesn't help) => keep trying, your char is stuck and will get unstucked automatically after ~ 5 failed attempts
if everything fails => wait for daily gs restart
if even that doesn't help => only now it's time to contact an admin - and don't forget to include detailed informations (account/char names, your IP, GS number, your timezone if you mention time, etc)