WebSocket agent connects but not updates linked attribute

Hi everyone. A have the next issue. I created asset. Added two attributes. In the first attribute i added agent link and attribute links and make a link two the sencond attribute. I created just simple python websocket server(after trying to get info from production websocket server that implemented with FastAPI in case there is some issues), created WebSocketAgent, put WS URL, saved it, added this agent to agent link to my attribute in asset. And what i see is that connection to my server was succesfully made. Manager created attribute links to my asset attribute and i have no messages from my server and no info in connected attribute. I see that my server accepted connection. In managers output i see that connection was succesfully made, but no asset updates in manager logs. HTTPAgent works well and provides information. One interesting fact that i send just dummy messages in string JSON from server every 5 seconds and periodically i have errors on server side ConnectionClosedError and in manager logs i see that websocket losts connections, but esnablish new one. All screenshots will be here. If anybody have ideas, please, help.

A new update from myself=)
If somebody will have this type of problem, pay attention to Message Match Predicte. Ot should be applied.