Hello everyone,
I am currently using streamlit to host some data dashboards. I logged in today and had the following error
“Failed to process a Websocket message. Error: Cached ForwardMsg MISS [hash=d8a4d7cb42736d2f68c9599e6da2321c]. This is not expected to happen. Please report this bug.”
I use streamlit version 1.40.1 and python version 3.14.4.
Getting nervous because other people in my organisation will want to view the dashboards frequently.
Welcome to the Streamlit community, and thanks for sharing your question! 
This “Failed to process a Websocket message. Error: Cached ForwardMsg MISS” error is a known issue that has affected several users, especially in versions prior to 1.45.1. The Streamlit team released a fix for this bug in version 1.45.1, so upgrading your Streamlit installation is the recommended solution. You can do this with:
pip install --upgrade streamlit
If you’re running Streamlit in Snowflake or a similar managed environment, there are additional workarounds, such as adding the following to your .streamlit/config.toml file:
[snowflake.responseCache]
initialResponseCache = false
But for most users, simply upgrading Streamlit resolves the issue. If you continue to see the error after upgrading, please share a minimal reproducible example and your deployment details so the community can help debug further. For more info and related discussions, see GitHub issue #11357 and Streamlit sanity checks.
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