Suddenly, cannot RDP to server using DNS names- only IPs

Question

We have a mix of Windows servers, one server is a Windows 2012 Datacenter server which has been working well until a few days ago. I try to logon to the server from a jump box (running Windows server 2019 Datacenter) using the server's DNS name (both short & FQDN) and it asks for my credentials but then shows the error "Your credentials did not work". I know my credentials are OK because I can log into the same server using the IP and strangely if I add a "." dot to the end of the server's FQDN, I can logon OK.

I cannot see any issues in any of the Windows Event Logs.
PING -a <DNS_Name> shows the correct FQDN name.
NSLOOKUP <IP> shows the correct FQDN name.

Does anyone know what could be the issue?
Why does adding a dot after the FQDN work?

Answer 1

I guess my question is more about why does the "." dot after the name work when the FQDN does not?

Read on here.
https://superuser.com/questions/1467958/why-does-putting-a-dot-after-the-url-remove-login-information

--please don't forget to upvote and Accept as answer if the reply is helpful--

Answer 2

Same error here

RDP:

FQDN: not work

IP: works

FQDN with a final dot: works

Answer 3

Might check that the clocks are in sync

Answer 4

Thanks, but if the clocks were out of sync then authentication would not work, whether using IP or FQDN. I guess my question is more about why does the "." dot after the name work when the FQDN does not?
PS: I found the following link:
https://borncity.com/win/2022/11/26/windows-remote-desktop-connection-issues-to-fqdn-since-october-2022/

This problem DID start recently!

Answer 5

Did you ever find a solution - we're having the same issue.