Hi Ben,
Thanks for the update.
1.Could you please confirm if you have installed RD session host role?
In MS remote desktop service deployment, RDSH role shall be installed in server that holds the session-based apps and desktops you share with users.
Users utilize the RDS CAL (installed on RD licensing server) to remote to the RDSH at the same time.
And you should find RD licensing diagnoser in RDSH while RD licensing manager in RD Licensing server.
2.Is there something else I should put in "Use the specified RD license server"?
Yes, you can use the IP address of RD licensing server.
3.Furthermore, please kindly confirm if you are using MS remote desktop service or other remote tools?
For the former one, you could check the quick deployment in below link if you don't have many servers.
https://nedimmehic.org/2017/01/21/deploying-remote-desktop-services-2016-step-by-step/
Please note: Information posted in the given link is hosted by a third party. Microsoft does not guarantee the accuracy and effectiveness of information.
If other remote tools, you could turn to their support as well. ( Appreciated if you could attach the screenshot of deployment for me to check further)
Thanks,
Jenny