The issue is host resolution. The users are specifying the license server by ip address, likely because they cannot resolve the hostname WIN-R9JB9KVTPKS. If that is the correct hostname of the license server, please have the users try adding an entry in their C:\Windows\system32\drivers\etc\hosts file that reads:
Then they can test by running a "ping WIN-R9JB9KVTPKS" command to see if it succeeds. If it does, then try running Fluent.