Why does nginx give a 500 error when a request is running for a long time?

Question

Nginx

ON LOCAL, EVERYTHING WORKS AS IT SHOULD.
There is a flash app on the server, there is a site scanner (you enter the site and it scans) when the site is small, it scans all the rules; when the site is large, error 502 comes to the browser console, can nginx give an error when some request processing time limit is exceeded or something I just don't understand this as a newbie.

Answer 1

The HTTP protocol is intended for short-lived communication sessions in the request-response mode. Request handlers, especially synchronous ones, should not take long actions and should not hold the connection.