All in One SEO uses the WordPress REST API

All in One SEO uses the WordPress REST API to communicate with the WordPress application.

This is a common way for plugins to connect to and communicate with WordPress.

However, some plugins may block access to the REST API. This can include security plugins and CDN services that have an option to block all communication with the REST API or just allow communication for logged in users.

All in One SEO only communicates when you make changes to the plugin settings, which requires that you’re logged in to your site and in the WordPress admin area.

If All in One SEO is blocked, then you will see a red warning notice at the top of the screen as shown below.

If you see this notice, try deactivating each plugin one at a time until the notice goes away. This should indicate which plugin is blocking access to the REST API.

If the problem still happens after deactivating all plugins, then switch to the default Twenty Twenty theme and see if the notice goes away.

If you’re using Cloudflare, we have a related article about Unable to Save Settings Due to Cloudflare Firewall Rules here.

All in One SEO v3.x does not use the REST API so this article does not apply if you have a version of All in One SEO lower than 4.0.