Getting Server response: UNAVAILABLE even after following the steps of "QUICK START kotlin gRPC on android"

Question

I have followed all the steps given in gRPC Kotlin QUICK START, I built and ran the server successfully and installed the Android app (Connected with adb over TCP in local network, same subnet, PC firewall is off). I ran the server using this command and got the expected output. $ ./server/build/install/server/bin/hello-world-server Server started, listening on 50051

But I am still getting an error when I click on the "Send gRPC Request" button, which says - "Server Response: UNAVAILABLE".

I have followed the steps given in the website as it is and still getting an error. When I type "Alice" in the message box according to the website, I have to get "Hello Alice". But that is not happening in my case. Is there anything else I have to do for this to work which is not mentioned in the website?

Thank you!