I just tried that and it still doesn't work.
What happens when you click the Pluto icon? Can you post a cell-pic?
Are you using stick or TV. I am using the Amazon fire tv edition and it worked fine on Sunday. Could be a stick problem.
Did you check and see if it got rolled into Paramount. I know my CBS All access (biggest waste of money ever!) got rolled into Paramount.
You might want to see if your log in works there. Just thinking out loud about stuff that changed March 4th.