Application shows "Waiting for Connection" - Reverse Porxy Error

Hemanth_L

Hi team,

I've been working with REI3 and encountered a WebSocket connection issue after deploying it behind IIS with a custom port. Here's my setup and the issue:

Setup:-
REI3 version: 3.10.2.7000
Hosting: Self-hosted on a Windows System using the exe
Port: Application running on port 8443
Reverse Proxy: Using IIS URL Rewrite to forward https://localhost → https://localhost :8443

The REI3 application loads correctly via the browser, but the WebSocket connection fails.

Issue:
The logs show the following:

2025/06/06 10:22:12 http: superfluous response.WriteHeader call from r3/handler.AbortRequestWithCode (handler.go:66)
2025-06-06 04:52:12 server aborted websocket request, websocket: request origin not allowed by Upgrader.CheckOrigin
This seems related to the CheckOrigin method rejecting WebSocket requests due to mismatched origin headers.

So Is there a recommended way to configure REI3 (or the Go code) to allow specific origins for WebSocket connections?

Thanks in advance for the help and for your great work on REI3.

gabriel

Not as far as I am aware.

I have seen r3 run behind different proxies and as long as you make sure that the request origin is not manipulated, it should work just fine. In your case, I would look at why the origin is changed and address this.

Unfortunately I have very little IIS experience, so cannot really help you here. Maybe someone else can step in.

Build 3.10.2.7000 does not conform to our public release of "REI3.10.2" - I assume this is a self-built version. In this case, you also could look at manipulating the source to allow for your case.