We have upgraded a system from Forms 9.1 to Forms 10.3.1. We have switched it from Laserfiche Authentication to use LFDS SSO. Users can successfully log into Forms without any issue. When going to Administration and looking at System Security and clicking Synchronize Users, we receive the error "The current user cannot be authenticated". 

Users that are in the list of Named Users show as invalid after a user has logged out. Any ideas of what user cannot be authenticated?