Getting 404 when trying to save changes under Settings\Discussions

I have WordPress 4.1.1 installed and am running into a problem when I attempt to save settings on the https://www.agentsof.cool/wp-admin/options-discussion.php page.

When I click the “Save Changes” button on the page I am sent to https://www.agentsof.cool/wp-admin/options.php and get a 404 error (which is odd as options.php does exist and trying to load that URL in the browser takes me to it).

I’ve tried this with all plugins disabled and the default 2015 theme activated and receive the same error.

Researching the issue on the WordPress forums, other users have run into this issue and in many cases it was either caused by an issue with mod_sec or mod_rewrite. I’ve checked and the .htaccess file in my public_html folder appears to be the default for WordPress.

Does anyone know what issues with mod_rewrite or mod_sec can cause this issue so I can give my hosting service some idea of what they should be looking for?