This user's password was reset recently.
This user recently woke up from a long period of inactivity.
based on the clue on theymos' email address "acctcomp15", it must be related to 2015 forum database leaked
so that might be your first login since 2015 and you've resetted your password to be able to login
it's a security precaution placed by theymos for all inactive accounts that just woke up
try emailing that email address given to you or do BitMaxz advice, check that link thread
or contact Cyrus or hilariousandco and ask them if they can unlock your account