The ClassicBattletech.com forums have been closed indefinitely due to a hacker attack.
From their announcement:
Due to a security breach the forums are being taken down indefinitely while the damage to the system is accessed. Because of the nature of this breach it is unlikely we will be restoring a backup of user accounts as it is impossible to know who’s passwords and accounts have been compromised.
We are currently accessing our options and will get the forums back up in one form or another as soon as possible. Thank you for your patience.
Jason M. Knight classicbattletech.com System Administrator