Make sure that software requirements to connect with the Active Roles Server are properly installed with the help of the KB article below:
https://support.quest.com/kb/4372666
Confirm that port 15172 is opened for both inbound and outbound traffic between servers. Try the following PowerShell command to test this:
From ITSS to ARS:
Test-NetConnection -ComputerName "ARSFQDN" -Port 15172
From ARS to ITSS:
Test-NetConnection -ComputerName "ITSSFQDN" -Port 15172
Finally, test the connection with the ARS server in your environment by using the ARS Management Shell and the following command:
connect-qadservice -proxy
Refer to the following screenshots for examples: