I got this error on client's DT Pro 2020, along with Error 2 which seemed to indicate encryption damage.  The bank account wouldn't connect - it said it was, but it wouldn't download.  Info on Error 2 said "change the password".  I disconnected the bank account and changed the password on QB, which re-encrypts the data.  Surprisingly, all fixed.  Bank connected and downloading.  Hope that helps.