How to Check and Set Windows terminal Services License Server
When setting Windows terminal server you need to set license server, which can be any windows server with the role license service install on it.

Or through powershell :
Install-WindowsFeature RDS-Licensing –IncludeAllSubFeature -IncludeManagementTool
Yet even after add this server to the deployment setting :

you can still get error about missing license server on the terminal preventing user logging on . To set this through Powershell do this steps, to check configured license server: :
$obj = gwmi -namespace "Root/CIMV2/TerminalServices" Win32_TerminalServiceSetting $obj.GetSpecifiedLicenseServerList()
To set the license server, use this powershell script (Download here)
# Specify the RDS licensing type: 2 - Per Device CAL, 4 - Per User CAL $RDSCALMode = Read-Host -Prompt "enter license mode: 2 - Per Device CAL, 4 - Per User CAL" # RDS Licensing host name (FQDN) $RDSlicServer = Read-Host -Prompt "enter RDS license server name (FQDN):" # Set the server name and type of licensing in the registry New-Item "HKLM:\SYSTEM\CurrentControlSet\Services\TermService\Parameters\LicenseServers" New-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Services\TermService\Parameters\LicenseServers" -Name SpecifiedLicenseServers -Value $RDSlicServer -PropertyType "MultiString" Set-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\Licensing Core\" -Name "LicensingMode" -Value $RDSCALMode
Good Luck