How to solve No "Upgrade: websocket" header?

[seanyinx]

Hi guys, I am trying to integrate a broker but run into the following errors when connecting to websocket in Docker (linux). However, running the same code on Mac works without any error. What could cause this issue?

2025-05-12T06:29:25.866232338Z [ERROR] TESTER-001.ExecClient-XNAS: Error on '_connect': WebSocketClientError('WebSocket protocol error: No "Upgrade: websocket" header')
Traceback (most recent call last):
  File "/algo/rockflow/execution.py", line 176, in _connect
    await self._ws_client.connect()
  File "/algo/rockflow/websocket/client.py", line 116, in connect
    client = await WebSocketClient.connect(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<4 lines>...
    )
    ^
network.WebSocketClientError: WebSocket protocol error: No "Upgrade: websocket" header

2025-05-12T06:29:25.871483463Z [ERROR] TESTER-001.DataClient-XNAS: Error on '_connect': WebSocketClientError('WebSocket protocol error: No "Upgrade: websocket" header')
Traceback (most recent call last):
  File "/algo/rockflow/data.py", line 143, in _connect
    await self._ws_client.connect()
  File "/algo/rockflow/websocket/client.py", line 116, in connect
    client = await WebSocketClient.connect(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<4 lines>...
    )
    ^
network.WebSocketClientError: WebSocket protocol error: No "Upgrade: websocket" header

Dockerfile (OS: kernel-6.12.5-linuxkit Linux (Debian GNU/Linux 12))

FROM python:3.13.3-slim

COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt

RUN pip install -U nautilus_trader==1.216.0

ENV PYTHONPATH "${PYTHONPATH}:/"

COPY algo/ /algo

CMD [ "python3", "/algo/demo_live.py" ]

Any help is appreciated.

[seanyinx]

Changing websocket protocol to wss solved the above issue.