Question: So, we migrated (not me, a contractor) our old domain to a new one, we were abc.local, now we are xyz.local. We also changed the DNS server from 1.2.3.4.5 to 10.9.8.7 (just examples, not real data here)

The migration added all workstation to the new xyz.local domain with no issues, however it did not change the DNS to the new one, and the old DNS is now gone.

I tried to change them via GPO running the netsh command, but I get "the remote procedure call was cancelled" error 8007071a when I try to apply the GPO from the DC.

My account is Domain admin. I cannot remote-in to those workstations now, so I cannot change the DNS. Remember that the workstations are joined to the new domain but they have the old DNS server configured which doesn't exist anymore.

Do you guys have any idea to try with to accomplish this?

Thank you.

Answer: 
If they are getting their IPs via DHCP, ensure you include the DNS server addresses in DHCP. Otherwise you're probably going to have to visit each machine and change their DNS server entries to the DC.

Either way, after it's changed reboot them so they are properly logged into the domain.
The only way to make your new domain work again from the static ip configuration of your clients is to make the DNS server available again.
This can be done by:

* Adding an additional IP address to the existing network interface (routing issues?)
* Second network interface in the old network 10.5.x.x (virtual/physical environment?)
* Setting up a new server with the old IP 10.5.x.x with DNS services which forwards all queries to the new DNS server 10.20.x.x

After you made DNS available for the clients again, you can change IP settings through GPO.