I am trying to sync my byteball wallet from a couple of weeks ago and it gets about a third of the way (35-45%) and then stops making progress. When I close and reopen the wallet, I get this error and the program closes:

Uncaught exception: Error: known bad go38q4DxyfamiSTzl5rmEBooilX0qGmoS36Wc9zVEY=: authentifier verification failed

Any ideas what to do? I have several full backups of the byteball folder, but for every one of them I run into exactly the same problem.