problem for websocket

[imankhorshidi]

hello
After authenticating with the websocket and sending the market, it returns me the following value and does not return the positions that are open.

User Position Subscription :
{
"method": "position.subscribe",
"params": {"market_list": ["BTCUSDT"]},
"id": 1
}
response :
{"id":1,"code":0,"message":"OK"}

position.subscribe after send to server.sign

whay response not to list positions?
Where can the problem come from?