Why does Socket.IO not always get messages from the server to the client?

Question

Nginx

Greetings.
I'm trying to implement a bundle - a socket.io server has been raised on Node.js. Communication with the outside world through nginx. The client is implemented in c# using Quobject/SocketIoClientDotNet . The problem is that messages do not always come from the server to the client. There is server-side logging that shows that the socket is sending messages to the client. But they are not always delivered - about 1 time successfully for 4-5 unsuccessful attempts. Can you advise where to look?
Nginks configured using habrahabr.ru/post/171757
Moreover, TIME_WAIT processes hang on the server, equal in number of unsuccessful attempts to send.
I ask for help in finding the reasons for this behavior.

Answer 1

1. Exclude nginx from the bundle to check who is to blame
   
2. Eliminate loss of connection with the server and test disconnect + timeout: try to break the connection on the c # side, maybe these will be the very unsuccessful attempts.
   
3. Logging for all operations socket.On(Socket.EVENT_, immediately on the client you can see that