If you are using LiteSpeed Cache, you might have noticed that it takes a while for updates to your Security Header settings to take effect. This is because LiteSpeed Cache can prevent the loading of our advanced-headers.php file (which contains the headers from the plugin).
The solution to this is to add rsssl_after_saved_fields to the “Purge All Hooks” list in the LiteSpeed Cache settings. This will purge the LiteSpeed Cache on every save of the Really Simple Security settings.
NOTE: This will not work for CSP Learning Mode. If you want to activate CSP: Learning Mode with LiteSpeed Cache enabled, you can additionally add rsssl_update_rules to the “Purge All Hooks” list in the LiteSpeed Cache settings. This will purge the LightSpeed Cache on every change to the headers (and will have an impact on your sites performance while Learning Mode is active). If the CSP is disabled or enforced, this should not be an issue.