Hi, the configuration test is exactly that - just a test, and is more suited to other automated requests, so copying those values and creating them won’t do anything much. Instead, perform a real certificate request (with ‘Request Certificate’) and if you need to copy the text values use Open Log File to copy and paste from.
You have opted to try using manual DNS validation, but you can also use http validation if the server is allowed to have port 80 open, the app will then temporarily serve http challenge responses as required. Alternatively if port 80 can’t be opened, or if the server just won’t be internet accessible, then the DNS challenge is fine.
I’d break the problem into chunks, get your certificate request working first (also, under Deployment choose ‘Certificate Store Only’ if you will not be binding the certificate to a website). Once that’s working you will need to look at ‘Show Advanced Options’ > Scripting to get the certificate to automatically bind to the RDP service every time it renews. There is a starter script we provide but it does need some edits generally, so check out this discussion as well: Post-renewal script for binding new certificate to Remote Desktop Gateway