I get 403 errors when RocketCDN is active
Error 403 (forbidden) indicates that RocketCDN does not have permission to take the assets from origin server and/or serve them on your domain.
Such issue is quite common and is caused by any kind of security plugin, firewall setting, and/or by hosting if there is any such mechanism active (especially if you use Shared hosting account type).
So first, try to deactivate your security plugin if you use one. If it solves your issue, contact the support of this plugin to know how to allow RocketCDN to take the assets from origin server and serve them on your domain.
If it’s not enough, you will have to contact your hosting provider to help you with this issue.