HTTP status code 0 - Error Domain=NSURLErrorDomain?

Question

I am working on an iOS project.

In this application, I am downloading images from the server.

Problem:

While downloading images I a

Answer 1

Status code '0' can occur because of three reasons
1) The Client cannot connect to the server
2) The Client cannot receive the response within the timeout period
3) The Request was "stopped(aborted)" by the Client.

But these three reasons are not standardized