Same with us.  Our old login information worked in October.  

However, when we tried to login a week ago, it just told us that our info was incorrect....same as what is happening to you.  I never got a prompt to change my User ID until I sent that email to the IRS.  I never got an email response, but a few days after I sent the email, I tried logging in again and they had somehow reset our account.  It then promoted me to change my User ID and I was able to get logged in and got everything filed.