How to properly debug socket io?

Question

Node.js

There is an application to which about 100 users are constantly connected. Application on node.js + socket.io. The application is launched through forever + clusters are used in the node.
The problem is that after every 2-3 days of operation, the socket.io port (running on port 8000) falls off (net::ERR_ADDRESS_UNREACHABLE error in the console) until you restart the application. At the same time, there are no errors in the forever log, that is, node processes do not die due to errors in the application.
It is not clear why the connection to the port is lost. It seems unrealistic to debug socket.io/docs/logging-and-debugging in the official way , because with 100 online visitors, the log is clogged instantly.
Are there any ideas on how to find out the reason for the drop in the port?