WordPress showing "Background Request Blocked"
If you use Wordfence on your website you may encounter the following error message while performing various changes on your WordPress website:
Wordfence Firewall blocked a background request to WordPress for the URL
https://www.mydomain.com/wp-admin/admin-ajax.php. If this occurred as a result of an
intentional action, you may consider whitelisting the request to allow it in the future.This is produced because the Wordfence Firewall can block background requests to the admin-ajax.php script. This feature is used to prevent certain types of attacks, but some plugins or themes could perform legitimate requests to that script and get blocked.
To resolve the problem, set the Firewall mode to ‘Learning’ from your WordPress Dashboard > Wordfence > Firewall > Firewall Status > Learning Mode.