[Samba] user with specific sambasid can not login

[Shawn Dakin]

For some odd reason a user with the specific sambasid
S-1-5-21-1545272169-3882205488-3325164475-21006
can not login on our PDC. The user gets the error "group policy client
service failed the logon"
If I increment the users RID to 21007 they can login.
I can not find any other users with the RID 21006 in my LDAP so no
conflict is apparent.
Does anyone have an idea as to what the problem is with this RID?
I assume some type of conflict with a previously existing user, but do
not know how to check apart from LDAP.
Are RIDs stored in another location?
-- 
Shawn Dakin (CNE)
Director of Technology
Newcomerstown Schools