Why is there a SIGPIPE signal (EPIPE error) when accessed from the Android browser?

Question

Android

Wrote a daemon in C++ (Linux). It listens until a request comes from an Android device.

And I did it universally: Android in the browser in the address bar you specify the IP address / site (on which the demon listens) and the demon itself sends a file in response, which is stored in the browser.

I use non-blocking sockets, TCP...

So, when a file starts to be sent, EPIPE arrives after a while (errno = 32 - Broken pipe). After this error, I close the socket.

I don’t know how it will work on other Android phones, but mine makes a second request and, lo and behold, it downloads the file from the 2nd time, without any EPIPE! I'm afraid that on other "cells", the file simply won't download...

If I do the same from my computer, then no EPIPE appears.

I would like to understand, to figure out why this is happening ... Who can tell me what to figure out what is happening ...