Unexpected response

[felrock]

Describe the bug
Running the client/server examples inside a docker gives me an 'Unexpected response from server' error. Using Python 3.8.

To Reproduce
Steps to reproduce the behavior:
Run examples as simple_server.py and simple_client.py on the same machine, except that simple_client is in a docker env.

https://python-socketio.readthedocs.io/en/latest/intro.html#client-examples

https://python-socketio.readthedocs.io/en/latest/intro.html#server-examples

Expected behavior
Terminal print that a connection was established.

Logs
Client:
Traceback (most recent call last):
File "simple_client.py", line 18, in
sio.connect('http://127.0.0.1:5000')
File "/usr/local/lib/python3.8/dist-packages/socketio/client.py", line 338, in connect
raise exceptions.ConnectionError(exc.args[0]) from None
socketio.exceptions.ConnectionError: Unexpected response from server

Server:
(2176514) wsgi starting up on http://127.0.0.1:5000
(2176514) accepted ('127.0.0.1', 42518)
connect 8b71ba2ba70f4ec3bd0491d76fcaba22
127.0.0.1 - - [25/Jan/2022 13:15:15] "GET /socket.io/?transport=polling&EIO=4&t=1643112915.2445767 HTTP/1.1" 200 349 0.000694