WebSocket server on SockJS not processing messages?

Question

JavaScript

The server suddenly stops processing messages, but heartbeat messages come from it.
I do not use proxying, several scripts are running on the server under different ports.
The server stops working normally after a random time, regardless of the ports used and the number of open connections.
In standard mode, each script processes up to 400 connections, so it's probably not a matter of load.
sockjs-node v0.3.7, node
v0.10.13 the situation under different versions is the same.
Perhaps someone has already encountered this, or does anyone have any ideas what to do?