Symptom #2: The app says "Please wait..." forever
If when you try to load your app in a browser you see a blue box in the center
of the page with the text "Please wait...", the underlying cause is likely one
of the following:
Misconfigured CORS
  protection.
Server is stripping headers from the Websocket connection, thereby breaking
  compression.
To diagnose the issue, try temporarily disabling CORS protection by running
Streamlit with the --server.enableCORS flag set to false:
bash
streamlit run my_app.py --server.enableCORS=false
If this fixes your issue, you should re-enable CORS protection and then set
browser.serverPort and browser.serverAddress to the URL and port of your
Streamlit app.
If the issue persists, try disabling websocket compression by running Streamlit with the
--server.enableWebsocketCompression flag set to false
