I got the same issues with one of my accounts. It is the account that I have a lifetime membership for.
Unable to log in on both accounts with underscore between 2 words as in XXX_XXX the other accounts with one word names got in just fine
Same here, I'm have two out of the six accounts I own and pay for are like they don't even exist. I didn't have this issue previous to today's patch.
Looks like it has something to do with the Overseer, once I started missions on those accounts then I could not get back in, getting invalid credentials. 4 accounts
2 of the ones I was locked out of work now. My primary account is still locked out. So it looks like there's some kind of progress Edit: Nevermind, three different ones are locked out now.
Having the same issue one on of my other accounts. Was using it just fine before patch, now get invalid credentials error.. and its my gold account, can only access my f2p account .