@anuj_jalan Hi, and welcome!
As of today, you can proxy gRPC traffic via Kong only by leveraging Kong’s TCP proxying capabilities (L4). This means indeed configuring a TCP Route/Service couple, but connecting to Kong’s streaming port (stream_listen), and not its HTTP proxying port. The fact that you received an HTTP 404 response code tells me that you connected your client to Kong’s HTTP proxy port (proxy_listen).
Note that Kong will have no understanding of the gRPC protocol from a L7 PoV, given that this port proxies raw TCP streams (L4). Nonetheless, this approach allows you to rely on Kong to handle routing, mTLS, Zipkin tracing, LB and circuit-breaking.
L7 gRPC proxying is upcoming in Kong 1.3 (ETA in the next couple of months), as announced in our recent community call. As of today, you can modify Kong yourself to support gRPC proxying; I have given instructions on how to do so in this thread, and some users have given it a try (successfully). This approach is similar to the one Kong 1.3 will follow.