Hello @elarthur ,
I suspect that the issue is most likely caused by a plugin/theme conflict, as such problems usually occur when there is another plugin or a theme setting that customize your WordPress login page. If you use some kind of membership plugin or a theme that leads the login pages to the default WordPress URL, please review their settings.
As for the website restore. There is no need to restore your entire website. You can simply revert the configuration to the default WordPress login URL by including the following snippet in the functions.php file of the active theme:
add_action( 'init', 'remove_custom_login_url' );
function remove_custom_login_url() {
update_option( 'sg_security_login_type', 'default' );
}
If you are a SiteGround customer, please contact our Technical Support team and we will further assist you.
Best Regards,
Tsvetan Mitev