ERR_CONNECTION_TIMED_OUT on EC2 instance

Hi all, hope you’re doing fine.

I’m using streamlit alongside FastAPI to make a nice UI for a portion of the API that I host on AWS.

The server starts the fastapi backend and call

subprocess.Popen(
        [
            "streamlit",
            "run",
            "./src/server/qa_ui.py",
            "--server.port",
            "3210",
            "--server.enableCORS",
            "false",
            "--server.enableXsrfProtection",
            "false",
            "--server.fileWatcherType",
            "none",
            "--server.headless",
            "true",
        ]
    )

The fastAPI (on port 3200) works fine, however, streamlit (on port 3210) raises an ERR_CONNECTION_TIMED_OUT but before the backend is queried by streamlit, which means it started ??

I’m just left with a blank browser page.
It works perfectly fine locally (and spawn in less than 10s).

Do you have any ideas?
I read about it and tried to disable server.enableCORS

Thanks in advance.