What can be the error when the socket connection is broken?

Question

JavaScript

For 3 months the application worked stably, no changes were made, and suddenly it began to turn off periodically (period from 15 minutes to 12 hours of stable operation), it displays an error:

Error: read ECONNRESET
    at TCP.onread (net.js:602:25)
---------------------------------------------
    at _destroy (internal/streams/destroy.js:34:15)
    at Socket._destroy (net.js:548:3)
    at Socket.destroy (internal/streams/destroy.js:32:8)
    at TCP.onread (net.js:602:17)

I don’t understand what exactly the problem could be, is it in the code or on the server? What to do?