When I try to remove one person from one notebook's Sharing list, I get "We were unable to process your request. Please try again later." The sharing icon is being removed at that moment, but it appears again after the sync. Same result for both Windows and web clients. There was one more notebook where I was removing the same user today with no issues. Here's a part of activity log: 10:50:56 [INFO ]   0% Revoking authentication token 10:50:56 [ERROR ]   0% EDAMUserException: errorCode=INVALID_AUTH parameter="authenticationToken"