Cleaning obsolete nameserver after takeover

after takeover to my new UCS 5.0-7 Pimary- and Backup node I’m facing some issues.

One is, that an “nslookup” from a Windows client is showing the old Windows Server DC’s still as nameserver in the msdcs database:

_ldap._tcp.dc._msdcs.abyss.lan SRV service location:
priority = 0
weight = 100
port = 389
svr hostname = ucs1.abyss.lan
_msdcs.abyss.lan nameserver = dc2022a.abyss.lan
_msdcs.abyss.lan nameserver = vdc2022c.abyss.lan
_msdcs.abyss.lan nameserver = dc2022b.abyss.lan
_msdcs.abyss.lan nameserver = ucs1.abyss.lan
ucs1.abyss.lan internet address =

The ucs1.abyss.lan is correkt (=Primary node). but the other 3 nameserver are obsolete since the old DC’s have been switched off.
Also the Backup node ucs2.abyss.lan is missing here.

I’ve searched all the LDAP and DNS settings in the UCS node but cannot find the entries, so suppose this is stored somewhere in the sqlite database used ny UCS.

Also /etc/resolve.conf is correctly capturing the nodes ucs1 and ucs2.

How can I get rid of the obsolete nameserver, and, how can I add the Backup node to the list of nameservers?