I've joined an AD server which I create in a virtual machine for testing purposes.
I can join the AD successfully from the Windows Domain Membership. However, when I test the authentication from Authentication Test in NTLM I always get "Error: Authentication failed".
I've checked in AD that the computer joined the domain. What I see is that after joining the domain if I refresh the status gets red.
Do you have an idea what the problem could be?
Thanks in advance.
There could be different reason for this issue (for example deleted computer account, no DNS result, bad credentials, permissions, etc.).
The troubleshoot this use the troubleshooting part of the following best practices article:
There you will find information about authentication debug log and troubleshooting via tcpdump to see whats happening on network level.
Please let us know if you have further questions.