Connection Error: Failed to process a WebSocket message

I have multiple Streamlit applications running behind a proxy. I did not have any problem until version 1.11.

Occasionally, when I am interacting with the streamlit, I get the following error message:

Connection Error
Failed to process a Websocket message (Error: Failed to retrieve ForwardMsg (hash=): Bad Request)

When I refresh the page, the error is gone temporarily, but it will show up again.

My proxy is handling /stream using websocket, and I did not have any issue previously.

When I downgrade the streamlit, the error is gone.

The main issue is related to:
which is not accessible.

Hi @kaveh ,

What streamlit version did u have before and what do you currently have right now? It seems like we have been doing some work with the WebSocket connections so it’s possible a bug was introduced at 1.11 or 1.11.1.

Thanks for posting the issue and hope to hear back.



Hi @willhuang

I was using Streamlit 1.9 without any issue. Once I upgraded to 1.11.1 for the vulnerability issue, I saw these errors. I even tried disabling CORS, XSRF, and WebSocketCompression but none of them worked. So I downgraded it back to 1.9 to make sure that it is still running without issues. I did not test it with 1.10.

I have many sliders in my app, and it usually happens when I am playing with the sliders. Once it happened, I checked the URL of /message?hash=... and it returned Error 404, and as of streamlit source code, if the hash code does not exist, the Message handler returns 404.