I once got the below message when trying to remote to a server after removing Active Directory from a server using dcpromo.
The reason I got the error message was because the server was configured to look at itself as a DNS server and because the DNS was also removed with the DCpromo command it could not find an Active Directory server for authentication.
The workaround I found was to add the following Dword to the registry:
In the folder:
Add the following key:
This will allow you to remotely log into the server. Just take note that it might take a while for the first logon to go through.