For quite a while, I have been getting an error message every single time I log in:

            AN ERROR MESSAGE HAS OCCURRED
             session verification failed. Please try logging out and back in again, and then try again.

This happens every time I log in, and I am ABSOLUTELY sure that my user name and password are entered correctly. I then go up to the top of the page and re-enter log in information, and it logs in every time. I just don't understand the need to do it twice every time. Can you help? Thanks.