I had same problem for over a week.  It is true it is an internal problem within the fire system.  Mine would go to a few steps at a time and then log out with same message. 

All of the helpful hints about getting new login or having to become authorized are not true for tax preparers with an existing TCC (transmitter control code).  All the rules about prior authorization are only for new TCC users.

SOLUTION:  You must verify your name is the same as when you signed up for Fire including capital letters if applicable, then you need lots of wine and a few beers to solve this particular problem.  You have to wait out the system until late at night.  Last Thursday night I tried to get on home computer late at night and it took me all the way to browse for files.  Unfortunately I had no files to transmit from home.  So finally Friday I took all IRS files and my software package home to load on my home computer.  I waited until 10:00 again on Fire.  After a few tries, maybe 10:30 I got all the way on and filed 33 clients.  I got email this morning that all were good.  You have to have patience and keep clicking on menu icon and next icons and keep drinking wine, but it works.  I am taking home 15 more tonight so if everyone could just stay off Fire tonight, that would be appreciated.