If your Terminal Server / Remote Desktop Server is unable to find a TS license server and is passed it's 120 day grace period you will not be able to connect via a standard Remote Desktop session.
To Connect you will need to use the following command:
This provides an admin connection and as such does not require a Remote Desktop license.
If you want to connect a Terminal Services License server have a look at the following article from Microsoft:
Connecting to a Terminal Services License Server