I normally get on briefly in the mornings to update doff missions for our five toons. This morning, between about 450 AM (ET) and 530 AM, I repeatedly got an Invalid Account or Password error. In each case, it happened immediately after I had finished with one toon, logged out and then tried to log in so I could update missions for another toon.
I'm very careful and cautious in entering my passwords, and I know I was entering it properly. What SEEMED to resolve the problem was shutting STO down completely and reentering the game -- my pwd was readily accepted that way. Each time. For all the remaining four toons.
I don't know if this is some sort of bizarre technical error or some sort of throttling attempt on multiple toon usage on accounts, but it is REALLY ANNOYING.