[Python] SignalR "Hub is not running you cand send messages" when subscribing to account with...

I'm working on integrating a real-time trading data feed using SignalR and the signalrcore Python client. I can connect to the hub successfully, and the account discovery API works fine. However, when I try to subscribe to an account via hub.send("SubscribeAccount", [account_id]), I consistently get this error:

ERROR - Error subscribing to account (attempt 1): Hub is not running you cand send messages

Console Output:


INFO - Bearer token loaded from config manager
INFO - Attempting to connect (attempt 1/3)
INFO - Starting connection...
INFO - Connection opened
INFO - Close message received from server
INFO - Connection established
INFO - Connection established successfully
INFO - Searching for accounts...
INFO - Found 1 accounts
INFO - Account found: S1MAY1613963393 (ID: 7873648)
INFO - Attempting to subscribe to account 7873648 (attempt 1)
ERROR - Error subscribing to account (attempt 1): Hub is not running you cand send messages
...

My Environment:

• Python 3.10
• signalrcore 0.10.1
• Server URL: wss://rtc.topstepx.com/hubs/user (with bearer token via Authorization header)

What I’ve Tried:

• Adding a delay before sending the subscription request
• Confirming that hub._connected is True
• Confirmed that the server returns a valid account in /api/Account/search
• Reconnecting manually before subscription attempt
• Subscribing immediately after on_open and after a short sleep

Relevant Code Snippet:


self._connection = HubConnectionBuilder()\
.with_url(
self.USER_HUB,
options={
"access_token_factory": lambda: self._bearer_token,
"skip_negotiation": True,
"transport": "websockets"
})\
.build()

self._connection.on_open(self._on_open)
self._connection.on_close(self._on_close)
self._connection.on_error(self._on_error)

self._connection.start()
await asyncio.wait_for(self._connection_ready.wait(), timeout=5)


await hub.subscribe_account(account_id)


# Inside `subscribe_account`
self._connection.send("SubscribeAccount", [account_id])

Question:


What does the error "Hub is not running you cand send messages" actually mean? Is this a server-side issue or something I’m doing wrong in the SignalR client setup?

Any ideas on how to debug or resolve this would be appreciated.

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