Recommended checklist

1. Purge Pilot Speed Pro, CDN, and host caches.
2. Test while logged out in a private window.
3. Enable Safe Mode and test again.
4. Run Diagnostics and review recent WordPress/server logs.
5. Restore the last known-good restore point if necessary.

WP_CACHE warning

Add define('WP_CACHE', true); above the wp-settings.php line in wp-config.php after making a backup. Pilot Speed Pro intentionally does not edit that file.

Foreign advanced-cache.php

The plugin does not overwrite a drop-in owned by another cache plugin. Disable or remove the conflicting cache system through its documented procedure before retrying.

HTTP probe blocked

Diagnostics provide specific guidance for HTTP 401/403, firewalls, ModSecurity, Basic Auth, CDN, and hosting restrictions.