How to prevent browsers from opening https subdomains?

Question

Nginx

Good time.
I encountered such a problem, a certificate is installed on the main domain and a forced redirect to https, after the user visits the main domain, his browser also tries to open all subdomains via https - accordingly, all styles, etc. do not plow. If you remove the forced on https from the main one, then everything is good, the guest came via http to the main one and uses subdomains without problems.
Is it possible to disable https browsers on subdomains? Or is it easier to transfer demos to another domain?

Front plows nginx, backend apache.

Answer 1

Perhaps you have a Strict-Transport-Security header with the subdomains option? Then loading of HTTPS even subdomains will be forced.