You are trying to connect via rdp to windows server 2012 r2 and you receive this error :
An authentication error has occurred.
The function is not supported.
Remote Computer: your hostname
This could be due to CredSSP encryption oracle remediation.
Download and install KB4103725 form Microsoft Update Catalog
After installing you need to restart the server.
The rdp defaul port is 3889.
To change this port :
In windows firewall, create a windows inbound rule on this new port on windows firewall.
- Start the registry editor. (Type regedit in the Search box.)
- Navigate to the following registry subkey: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp\PortNumber
- Click Edit > Modify, and then click Decimal.
- Type the new port number, and then click OK.
- Close the registry editor, and restart your computer.