How to fix Unyson Page Builder Error: "error: Forbidden" or "error: Not Found"?

Usually, such issue occurs in the following cases:

- when false positive mod_security rules module is activated on your server;

- when mod_rewrite module is deactivated on your server;

Please contact your hosting provider and check these points: 

ask them to turn OFF false-positive mod_security and to turn ON mod_rewrite module on your host.

The mod_security and mod_rewrite must be inappropriate states.

These recommendations would solve the issue.

As last resort we recommend you to change your current hosting to migrate on such hosting as https://www.siteground.com/wordpress-hosting.htm

It includes all optimal settings, SSD storage, high memory limit, 10 GB free space, CDN, and many other powerful features.

The optimal plan is - StratUp Plan.