I've built a VDI with 3 Windows server 2019 on Hyper-V on Windows 10 pro latest version. testing it on my local network, when clients connect to the RDS server, gateway manager shows the connections are based on HTTP and UDP only, no word about HTTPS.
i have my own enterprise CA and clients first connect through an SSTP VPN which is hosted in one of those servers and then use the internal DNS name of the RDS server to connect to it. the reason for the SSTP VPN is to first secure the connection and second to access the internal DNS servers.
without VPN the client can't use the internal DNS names of the servers.
I have an external domain name pointed to my VPN server which is globally resolvable and clients can easily connect to my VPN server first and then have access to the internal DNS server.
here is in default gateway manager
i get this error when i try to turn of UDP:
here is how the connection looks like when a client first connects to the SSTP VPN and then to the RDS host using RDP.
Everything is set up correctly AFAIK, the certificates are ok, PKIVIEW is all ok, the connection is ok. i just don't know why i'm not seeing HTTPS connections in Gateway manager.