How do I allow Cross-Origin Resource Sharing (CORS) with Magento on Fleet?
You can do this via .htaccess for static files.
Header set Access-Control-Allow-Origin: <domainname>
For dynamic content you'll need to set headers via PHP.
Note that this must be done before any output is sent.
You can specify
* to allow any domain to access your site.
Note that it may be necessary to set other headers.
You can find more information about CORS at the following pages: