[Samba] samba dc dns issue

[Alex]

Hello Kris,

> You might have a "chicken and the egg" issue with DNS.  The prospective
> (soon-to-be-joined) DC has itself listed in resolv.conf -- so it looks
> there but can't find an entry for an existing DC to join?  Remove the
> self-referential entry and try again.  Add it back after the join.

Since I've already joined the domain, I don't think that should be an issue.
Anyway, I've just removed the host itself from resolv.conf and ran:
samba_dnsupdate --use-samba-tool --fail-immediately -d 5

which resulted to:
...
ERROR(runtime): uncaught exception - (9717, 'WERR_DNS_ERROR_DS_UNAVAILABLE')
  File "/usr/local/samba/lib64/python3.6/site-packages/samba/netcmd/__init__.py", line 186, in _run
    return self.run(*args, **kwargs)
  File "/usr/local/samba/lib64/python3.6/site-packages/samba/netcmd/dns.py", line 945, in run
    raise e
  File "/usr/local/samba/lib64/python3.6/site-packages/samba/netcmd/dns.py", line 941, in run
    0, server, zone, name, add_rec_buf, None)
Failed update of 25 entries

and
samba_dnsupdate --fail-immediately -d 5
...
Ticket in credentials cache for VM-DC4$@DOMAIN.COM will expire in 35999 secs
Starting GENSEC mechanism gssapi_krb5_sasl
GSSAPI credentials for VM-DC4$@DOMAIN.COM will expire in 36000 secs
; TSIG error with server: tsig verify failure
update failed: REFUSED

-- 
Best regards,
Alex