G’day webtexweb,
This plugin does not change any settings on your website.
Did you change your WordPress Address (URL) and Site Address (URL) to https? If you did, and your site can’t detect https, then you’ll be locked out.
You can force your site back to http while you sort out your problems by temporarily adding the following lines to your wp-config.php file, changing the domain name to your domain name of course:
define( 'WP_SITEURL', 'https://example.com/wordpress' );
define( 'WP_HOME', 'https://example.com/wordpress' );
You might also want to temporarily add this to your wp-config.php file, to stop this plugin detecting https and overriding some other mechanism on your website:
define('SSLFIX_PLUGIN_NO_HTTPS_DETECT', true);
Then reinstall this plugin and check what it says for HTTPS detection on either its settings page or the Tools page.
https://ssl.webaware.net.au/https-detection/
cheers,
Ross