Can you use Adobe Reader Pro licenses on terminal server

Hi all,

Client has 3x Adobe Reader Pro serial numbers.

We are having issues with activating one of these on a terminal server.   Is the issue that it's a terminal server?   Or is something else going on?

Actual error suggests that all the serial numbers are in use.    We have deactivated one of these as suggested, but it didn't make a difference, so I suspect that maybe this warning is a false flag and the real issue is terminal server.

Please advise.