Why does the page on the server take a very long time to load, but not on the local one?

Question

Yii

DB is the same. Everything is 1 in 1. But on the server it can take about 40 seconds to load or fall into a timeout. It loads locally in a couple of seconds. So with only one page, the rest load quickly. The page does not contain large amounts of data: a YouTube video and a few fields.
40 seconds hangs, and then renders in a couple of seconds.
I can't leave the page.
Where and how to look for the cause? How to debug this?