How to find out the reason why pong is not getting a response from the client by the socket.io server?

Question

cloudflare

Good evening.

The essence of the problem is that when the online increase is +5-7k, laravel-echo-server does not receive a response from the pong browser (although it sent it) within 5 seconds, as a result of which it cuts the connection by timeout.
As soon as the server wrote that the timeout , the


Browser stopped receiving messages from it.


Moreover, until this moment, the messages were received cheerfully and without problems, that is, the browser receives messages from the server quickly, but the delay is taken from the browser to the server from somewhere.
Moreover, nodejs is not even proxied through nginx, no matter how much nginx has been sharpened without it, it turns out to work better, but nodejs is proxied through Cloudflare.

In total, I think either this queue of pong responses from the browser is coming out in Nodejs and as a result does not have time to be processed on time, or Cloudflare for some reason delays the pong response from the browser to the server. But I still don’t understand how to debug all this and identify the culprit, I would be grateful if someone tells me how this can be identified and will give at least some impetus.

In any case, thank you all for your time.

New information:
Today I decided to check and connected from one computer directly without Cloudflare, the sockets were interrupted with cloudflare almost synchronously, that is, the reason is not in it.
And new skins