Establish websocket connection from docker container failed: ConnectionRefusedError: [Errno 111] Connection refused

I tried to establish websocket connection from docker container, it failed. The target server is running, and establish http request is ok.

msg_cli = SimpleClient(address=f"ws://{server}:5000", manId=user_id)

The error infos are：

File "/opt/conda/lib/python3.7/site-packages/jd_api_test/tools/msg_push.py", line 24, in get_msg
    msg_cli = SimpleClient(address=f"ws://{server}:5000", manId=user_id)
  File "/root/.local/lib/python3.7/site-packages/chat/simple_ws.py", line 34, in __init__
    timeout=timeout
  File "/root/.local/lib/python3.7/site-packages/websocket/_core.py", line 605, in create_connection
    websock.connect(url, **options)
  File "/root/.local/lib/python3.7/site-packages/websocket/_core.py", line 247, in connect
    options.pop('socket', None))
  File "/root/.local/lib/python3.7/site-packages/websocket/_http.py", line 130, in connect
    sock = _open_socket(addrinfo_list, options.sockopt, options.timeout)
  File "/root/.local/lib/python3.7/site-packages/websocket/_http.py", line 205, in _open_socket
    raise err
  File "/root/.local/lib/python3.7/site-packages/websocket/_http.py", line 185, in _open_socket
    sock.connect(address)
ConnectionRefusedError: [Errno 111] Connection refused

Thanks for your help!