Why is the HTTP referer header not passed to the statistics?

Question

Analytics

Hi, perhaps you can help solve the problem or point me in the right direction.
The site has Google Analytics and Yandex.Metrica installed. They work great and show everything. Site on https. BUT! They always show only Direct traffic as the traffic source, which means they don't get the HTTP referer header. Do you have any suggestions because of what it could be and in which direction to dig?

Answer 1

dig in the direction of the server logs,
you will quickly see that the referrer is not there