Network Connectivity between Citrix product and the Citrix License server is necessary for normal operation. Please see steps below for troubleshooting steps.

Instructions

1. Check if the License Server is powered on 
2. Check if the License Server is responding to network requests.  From your Delivery Controller ping the license server by hostname and by IP address
   • For more information on troubleshooting network connectivity, see https://technet.microsoft.com/en-us/library/bb727023.aspx
   • For more information on grace periods, see https://docs.citrix.com/en-us/licensing/11-14/technical-overview.html
3. Make sure firewall settings on the License Server allow inbound rules for licensing related programs and services including 
   • * C:\Program Files (x86)\Citrix\licensing\ls\Citrix.exe 
   • * C:\Program Files (x86)\Citrix\licensing\ls\lmadmin.exe 
   • * C:\Program Files (x86)\Citrix\Licensing\WebServicesForLicensing\Apache\bin\httpd.exe
   For more information, see https://docs.citrix.com/en-us/licensing/11-14/getting-started.html#firewall
   For Information of ports used by Citrix, see https://support.citrix.com/article/CTX101810
4. Make sure the Citrix Licensing Daemon is running on the License Server.
   See  https://support.citrix.com/article/CTX200151 for troubleshooting steps