I am exactly in this situation:
The RDS role was installed erroneously, and the grace period to decide the licensing mode was left to expire; when I tried to connect, I was greeted with (the Italian localized version of) this message:
Since we use RDP just for remote administration, after reading around that two administrative connections are "built in" if the RDS role is not installed, I removed the RDS role and rebooted; as a result, it was impossible to connect - the 3389 port wasn't even open.
Then, I found that the Remote Desktop setting in the System properties dialog (the same that you would use to enable RDP on a non-server machine) wasn't enabled; I enabled it, and now when connecting I get this message:
(in English that would be "License error - Please contact the administrator")
which is in fact different from what appeared before (when the RDS role was enabled), but it still isn't letting me in. I restarted the various RDP-related services to no avail.
This appears exactly the same both when connecting with
mstsc from a Windows machine (with and without
rdesktop from a Linux machine (with and without
-0, which AFAIK now shouldn't even have an effect on Windows >2008 Server).
Is this going to go away after yet another reboot or I have to perform some other magic to convince this thing to let me in? No, rebooting didn't fix anything. Suggestions?