I was entering the first of three shops tonight. When I tried to advance to a new page, suddenly I received the login page with the message, "login expired or invalid." I logged in, continued. The problem persisted. Now it does it continually. It will flash the landing page briefly, then flash to the login.
Do not read so much, look about you and think of what you see there.
Richard Feynman-- letter to Ashok Arora, 4 January 1967, published in Perfectly Reasonable Deviations from the Beaten Track (2005) p. 230