If you trying to connect to a RDP server and you get this error:

Remote logins are currently disabled.

Description: The user is attempting to log on to a Terminal Server where an administrator has disabled logon by issuing the CHANGE LOGON /DISABLE command. In order to enable logon, the CHANGE LOGON /ENABLE command must be issued.

You would require the help of psexec utility to gain access to the command prompt of the desired server. You the below syntax:

psexec.exe “\\SERVERNAME\ change logon /enable”

Overview of the CHANGE LOGON Command
The change logon command uses the following syntax:
change logon /enable | /disable | /query
The parameters that are used by the change logon command are:
/enable: Use this parameter to turn on logons from client sessions.
/disable: Use this parameter to turn off any further logons from client sessions. Currently-logged-on users are not affected.
/query: Use this parameter to display the current logon status.

NOTES: The change logon command applies to logons from client sessions. Logons from the console session are not affected.