Step-By-Step: Implementing Azure AD Password Protection On-Premises

appreciate the write up. I was wondering if you could help understand an error i'm receiving... I have a single proxy service in a hybrid environment and installed the dc agent on a single dc... I got confused on the writing of the proxy.exe.config file... we don't have a http proxy in our environment..so I'm guessing that should be the proxy service server name.  i've restarted the proxy config service and dc agent service.. still seeing this error:

"One or more Azure AD Password Protection Proxy servers were found in the forest but this machine was unable to establish network connectivity to any of them..."

i see the inbound firewall rule for port 135...and i'm able to telnet to the port on proxy service server from dc agent server... is there some other communication that i'm not seeing?

appreciate the time and effort. thanks.