On a freshly installed Windows 2012 R2 server you cannot RDP.
Check all of the following:
- If the server was commissioned using the WHMCS Virtualizor_cloud module, use VNC and make sure the Administrator user has a password.
You cannot use RDP is the administrator username doesn’t have a password.
2. RDP must be enabled in User Mode TCP
Enable the rule that permits access through the Windows Firewall.
1. Search for Firewall and open “Windows Firewall and Advanced Security”.
2. Find the rule “Remote Desktop – User Mode TCP-in” and ENABLE Rule
See this article to enable RDP in user mode: