Hi,
could you elaborate a little bit further about what you did when this happened? Do you have multiple servers? On which one did you see this error?
It looks like you have multiple servers and this one can not reach srv-ad-master.dominio.intranet as some ports appears to be blocked. Is there a firewall in between?
Could you please post the output of samba-tool drs showrepl on both servers?
Have you checked this article for firewall ports?
/CV