Why does PageSpeed ​​Insights say that gzip compression is not working?

Question

Nginx

I run the site through GidZipTest, it says that compression is enabled.
I run through PageSpeed ​​Insights, writes that it is recommended to enable text compression.
Please tell me what could be the problem and who to believe from them?

Answer 1

In PageSpeed ​​Insights it is written exactly where compression is not enabled.
Must check for relevant urls. It may not be html for example. And this, by the way, may be some external resources.