Enable your site to have a different domains for HTTP and HTTPS.
wp-config.phpdefines the needed constants.
define('FORCE_SSL_ADMIN', true); define('HTTPS_DOMAIN_ALIAS', 'example.org');
The plugin scenario assumes the site domain is example.com but there is no https certificate for it. Instead there is a https certificate for example.org, which has been defined as the HTTPS_DOMAIN_ALIAS.
In a WordPress Network installation the HTTPS_DOMAIN_ALIAS can be defined as *.example.org and then <domain.tld> will be redirected to .example.org. This plugin is designed to be compatible with the WordPress MU Domain Mapping plugin.
Possible values of $location when calling this function