Cannot open the identity safe vault in firefox

Windows 10, Firefox 51.0.1, Norton Identity Safe, three PCs.  Saturday everything was working fine.  Yesterday morning I attempted to open the identity safe vault in Firefox.  I got the 'something went wrong try again' error.  Now all I get is the spinning wheel on the 'Unlock your vault - validating password' page on all three PCs.  I have logged out of my Norton account both from NS and the 'ID safe Unlock your vault' page. I have restarted and shut down/restarted all three PCs - no change.  I have rebooted my router - no change.  I have removed ID safe from FF, closed FF, restarted the PC, reinstalled ID safe - no change.  I installed ID safe for the first time on a second account on one PC - no change.  I can access the vault online with no problem.  It also works in Internet Explorer.  There must be something wrong with my account at the Norton end. How do I get someone at Norton to really look into this?