For offline notifications, connection endpoint replies back 502 Bad Gateway response code to Router Endpoint instead of replying 404 Not Found

[MaenMax]

Connection endpoint replies back 502 Bad Gateway response code to Router Endpoint instead of replying 404 Not Found. When sending a notification while the browser is disconnected (offline), connection endpoint (or Rust websocket server), reports 502 to the Python router, a response code that is not expected by the router. In the original implementation, and in such scenario, router used to receive 404 from the Python connection node.