I had a recent logging in problem. Somehow, I'd signed out. To sign back in I needed my user name, email address and password.

Since first registering I could not remember which email I had originally used (I use a number, for different uses, mainly to minimise spam overload); the password (that's always changing); and user name. I was continually logged out, and discovered in the end - when I saw one of my earlier posts in a thread - that I had been using the wrong user name. I had forgotten to add the D to the end.

Trial and error, but I got there in the end.