What can cause slowdowns with the work of the VK Callback API?

Question

PHP

A person from the proposed list selects the item that interests him. Let's say I chose 2, and the script starts parsing from the site (which is under the proposed number 2) using Curl + PHPQuery and throwing in response. Only here it happens that the slowdown in responses to the user occurs for 5-10 seconds. With what it can be connected? The site from which the info is parsed works well through the browser, what could be the main jamb?

Answer 1

well debug it.
See how long the request from VK takes.
after what time the server receives it and sends ok
what happens next. like a parse.
after what time the sparse material goes to VK.
somewhere along the way and you will find a big delay. there is a problem