Windows Server 2003 SP3: "the specified network name is no longer available"

I have a network, where the Active Directory Domain Controllers run Windows Server 2019.

We have an old SharePoint server running Windows Server 2003 SP2 running as a virtual machine on an old Microsoft Windows Server 2012 R2 Hyper-V server.

We recently had to rebuild our domain controller. That used to run Windows Server 2012R2, but now everything got upgraded to Windows Server 2019 except the old Hyper-V box and the old SharePoint virtual machine.

I added the Hyper-V server to the domain with no issues. I was able to make the old SharePoint server as a Workgroup computer, however when I try adding that to the new domain controller, I receive the error message:

The specified network name is no longer available

Upon entering the domain name and clicking the OK button, I receive the dialog box requesting my system admin domain credentials. I successfully enter the credentials, the login dialog box disappears but in its place comes a message box that states that the network name is no longer available.

I did try changing the computer name prior to joining the domain to something new. Although that should not be a factor, I covered my bases. That had no effect.

Thoughts?