I'm not entirely sure what the issue might be, but it sounds like the Samba server doesn't recognize the user anymore.
Can you please give me some more information? Especially:
- What is the full DN of the other container you've moved the user into?
- Please check whether or not the user object exists in both the OpenLDAP and the Samba 4 directories. For that you can use the two commands »univention-ldapsearch uid=xpto dn« for the OpenLDAP directory and »univention-s4search cn=xpto dn« for the Samba 4 directory.
- Verify that the target container exists in the Samba 4 directory with similar searches (try »univention-s4search | grep Domain-OUSITE1-Users«).
I seem to remember that containers in the Samba 4 side must be of type container, not of type organizational unit (check the objectClass attribute in the output of »uinvention-s4search« in order to see which type it actually is). I don't remember why that would be the case, though. But it may be worth checking.
Also check whether or not there are conflicts in the synchronization between the OpenLDAP and the Samba 4 directory. Use the command »univention-s4connector-list-rejected«.