I've been having problems trying to log in over the last few weeks. I have a 'locked username' and it's driving me mad I really don't want to change my username or password but may have to!
I had the same problem a few months ago and tried everything I and other people could think of. Nothing worked until I changed my password. Once I had logged on a few times using the new password the problem stopped. Sorry to be the bearer of bad news.