[Samba] samba_upgradedns returned an error "Unable to find uid/gid for Domain Admins "

[Markus Dellermann]

Hi at all,

i´am using samba 4.3.4 as "ad", "migrated by classicupgrade" some time ago 
from an nt4-domain. 

By trying 
samba_upgradedns --dns-backend=BIND9_DLZ

i get the following error:

Traceback (most recent call last):
  File "/usr/sbin/samba_upgradedns", line 262, in <module>
    paths, lp.configfile, lp)
  File "/usr/lib64/python2.7/site-packages/samba/provision/__init__.py", line 
298, in find_provision_key_parameters
    raise ProvisioningError("Unable to find uid/gid for Domain Admins rid (%s-
%s" % (str(names.domainsid), security.DOMAIN_RID_ADMINISTRATOR))
samba.provision.ProvisioningError: ProvisioningError: Unable to find uid/gid 
for Domain Admins rid (S-1-5-21-855155194-824588496-1214258294-500

"Domain Admins" seems to be in "ad"

wbinfo -i 'MYDOMAIN\Domain Admins'
MYDOMAIN\domain admins:*:3000008:3000008::/home/MYDOMAIN/domain admins:/bin/
false

I know, it was working "some time ago"
I deleted some groups like 
"domainadmins:!:15008:administrator,root"
from /etc/groups -i have thought I didn't need them anymore

Could this be the problem?

Where should I search?

Thank you for all your hints!

Markus