FlyingPress relies on the WordPress REST API to perform key actions like saving settings, purging cache, and preloading within the dashboard.
If you see the error "Unable to communicate via REST API", here are possible causes and solutions:
1. REST API Blocked by a Plugin or Security Layer
Some plugins—especially security or optimization tools—may block access to the REST API.
Visit:
https://your-site.com/wp-json/
If this URL doesn't load properly, your REST API is likely blocked.Review your security/performance plugins and disable any option that restricts the REST API.
If you use a firewall or WAF, ensure it allows REST API traffic.
2. Server Overload or Downtime
A slow or overloaded server may prevent REST API responses.
Check if your site is online and responsive.
If you're on shared hosting or limited resources, increase the cache preload delay in FlyingPress settings to reduce load.
3. PHP Errors or Plugin Conflicts
Errors in FlyingPress or another plugin can break the REST API.
Review your site's PHP error logs via hosting panel or
/wp-content/debug.log.Look for errors related to FlyingPress or any other plugin.