问一个 websockets 的问题

我用 python 写了一个 websockets 例子， 服务端和客户端在一台服务器上就可以正常通信，
放在不同的服务器就会提示
error：websockets.exceptions.InvalidMessage: did not receive a valid HTTP response 。
是不是网络的问题，不过我服务器防火墙上的端口都打开了。

sever.py 服务端


import asyncio
import websockets

# 检测客户端权限，用户名密码通过才能退出循环
async def check_permit(websocket):
    while True:
        recv_str = await websocket.recv()
        cred_dict = recv_str.split(":")
        print("接受",cred_dict)
        if cred_dict[0] == "admin" and cred_dict[1] == "123456":
            response_str = "congratulation, you have connect with server\r\nnow, you can do something else"
            await websocket.send(response_str)
            return True
        else:
            response_str = "sorry, the username or password is wrong, please submit again"
            await websocket.send(response_str)

# 接收客户端消息并处理，这里只是简单把客户端发来的返回回去
async def recv_msg(websocket):
    while True:
        recv_text = await websocket.recv()
        print("消息:",str(recv_text))
        response_text = f"your submit context: {recv_text}"
        await websocket.send(response_text)

# 服务器端主逻辑
# websocket 和 path 是该函数被回调时自动传过来的，不需要自己传
async def main_logic(websocket, path):
    await check_permit(websocket)

    await recv_msg(websocket)

start_server = websockets.serve(main_logic, '0.0.0.0', 8765)

asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()



#### client.py 客户端

import asyncio
import websockets

# 向服务器端认证，用户名密码通过才能退出循环
async def auth_system(websocket):
    while True:
        cred_text = input("please enter your username and password: ")
        await websocket.send(cred_text)
        response_str = await websocket.recv()
        if "congratulation" in response_str:
            return True

# 向服务器端发送认证后的消息
async def send_msg(websocket):
    while True:
        _text = input("please enter your context: ")
        if _text == "exit":
            print(f'you have enter "exit", goodbye')
            await websocket.close(reason="user exit")
            return False
        await websocket.send(_text)
        recv_text = await websocket.recv()
        print(f"{recv_text}")

# 客户端主逻辑
async def main_logic():
    async with websockets.connect('ws://(server 公网 ip):8765') as websocket:
        await auth_system(websocket)

        await send_msg(websocket)

asyncio.get_event_loop().run_until_complete(main_logic())