This has happened once before and I found that re installing was a waste of time. If only I can find my post from time first time this happened, I know how to get around this, I think it has something to do with the cog at the top right of the log in. You don't need to do anything, but go into that and back out and I THINK it should get around it, may take a few times. That's what I think I did last time....