If you ever get the error message in the title when connecting to a RDS session host while your licenses are OK, try the following:
- Open Regedit on the host(s)
- Navigate to HKLM\System\CurrentControlSet\Control\Terminal Server\RCM
- Take ownership of the GracePeriod key
- Delete it
- Reboot server
Found on:
http://www.stopdoingitwrong.co.uk/server-2012-rds-there-are-no-remote-desktop-license-servers/