This new setting, which I believe cpanel has enforced in one of my recent cpanel updates to only the origin domain, needs to be changed on my server. I can see that there is a cpanel option called "Use X-Frame-Options and X-Content-Type-Options headers with cpsrvd", but this notes that it sets the "X-Frame-Options" to "SAMEORIGIN". I need it either unset or set to ALLOWALL or the equivalent. I've attempted to follow this guide: jamesmaurer.com/enable-or-disable-x-frame-option-sameorigin.asp and tried both "all versions" of apache, and the specific version option. Restarted Apache through all the testing, and nothing worked. Is there any other option available to me, while staying inside cpanel GUI or .htaccess, or will I need to contact my support provider to do this via SSH command line? If possible, I'd like to be able to set it on a per-site basis.