Unfortunately we did not make a note of the exact error, but if you are facing this problem, we discovered the cause was due to the netlogon service starting before the DNS service. This caused the server to not recognise itself.
The fix below is the solution
- Open regedit on the server
- Locate HKLM > System > CurrentControlSet > services > Netlogon
- On the right locate DependOnService
- Double click to open on a new line at the bottom enter DNS
- Click OK and reboot the server.
Once we made the above changes, the server would reboot and worked as expected. Clients were once again able to authenticate.