Uvicorn server starts but "The connection has timed out" on the Browser

When I execute the following code (basic Hello World from the doc):

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def root():
    return {"message": "Hello World"}

And start the uvicorn server from my distant server (accessed through ssh) with:

uvicorn main:app --host 0.0.0.0 --port 8000 --reload

And finally access https://MY_IP_SERVER:8000

I get:

The connection has timed out

Problem: it used to work...

I tried to check all the processes corresponding to uvicorn and to kill them, I also restarted the server, but still the same

Any idea ?