Try re-installing steam and deleting all old game files (be sure to backup to external drive so you can copy them back after you re-install steam) that solved my problem with connection issues. Also you could try going back to the old steam UI if you have the new one, for some reason when I have the new beta UI installed I can't pick up group servers and get connection issues.
For the sake of the people on your team, I hope you don't fix this issue.