My app stopped working properly

Using Streamlit
1

My app mongolia-tour-calcullator-inbound-tours.streamlit.app , deployed from GitHub suddenly stopped working properly. It was working Ok just yesterday with Private repository and I did not change anything.

It is giving this error notification:

Oh no.

Error running app. If you need help, try the Streamlit docs and forums.

How to resume the app back to work or know what is the problem?

2

Hey there, thanks for reaching out and welcome to the Streamlit community! :partying_face: You’re not alone—many folks run into the “Oh no. Error running app.” message on Streamlit Community Cloud, especially when nothing has changed in their code or repo. This error can be caused by several things: exceeding resource limits, dependency issues, problems with the repo (like access or file structure), or even temporary platform outages.

Here’s what you can do to troubleshoot and (hopefully!) get your app running again:

  1. Check Cloud Logs: Go to your app dashboard, click “Manage app,” and review the Cloud logs for any error messages. These logs often point to missing dependencies, resource issues, or file path problems (Streamlit Community Cloud Management).
  2. Reboot the App: Sometimes, a simple reboot clears memory or resolves transient issues. You can reboot from your workspace or Cloud logs (Reboot your app).
  3. Resource Limits: If your app exceeded CPU or memory limits, you’ll see this error. Try optimizing your code, using caching (st.cache_data), or reducing data loaded at startup (Resource limits).
  4. Repo Access: If your repo is private, ensure your GitHub permissions haven’t changed. Streamlit needs access to your repo to deploy the app (Community Cloud Status).
  5. Dependencies: Double-check your requirements.txt for typos, unnecessary packages (don’t include built-in modules), and version mismatches. Only list packages you actually use (Managing dependencies).
  6. File Structure: Make sure your entrypoint file (e.g., app.py or streamlit_app.py) is in the correct location and named properly (App not loading when running remotely).

If you’re still stuck, please share your repo link (if possible), requirements.txt, and any error messages from the logs. The community loves to help debug! And if you have a minimal reproducible example, that’s even better. Folks, feel free to jump in with your insights or similar experiences!

Sources:

3

i just had this happen when 1.59.1 was released. add streamlit==1.59.0 to your requirements.txt, should fix it

4

I’d start by checking the deployment logs first—they usually reveal the actual cause instead of the generic error page. If nothing changed in your code, it could be a temporary deployment issue or a dependency update, so try rebooting the app and redeploying it.

5

This might be caused by a bug in pyarrow 25.0.0: [C++][Python] SIGSEGV in bundled mimalloc mi_thread_init when libarrow is first loaded on a non-main thread that exits (mimalloc 3.3.x, pyarrow 25.0.0) · Issue #50471 · apache/arrow · GitHub
Update to Streamlit 1.59.2 or pin pyarrow < 25.0.0 to prevent this crash.