Starter content download problems (CORS)

Hi there, after having installed the Rosa2 lite theme, I could not install the demo starter content package because of CORS error : Error: status 500; type cors at t.value (dashboard.min.js?ver=1.3.4:formatted:28826) => https://demos.pixelgrade.com/rosa2-lite/wp-json/sce/v2/data

I got the same fetch CORS error when I try to click on “Refresh your connection” => https://pixelgrade.com/wp-json/wupl/v2/front/get_licenses

Is there a way to bypass these errors ?
Is there a location where I could download the XML file of the starter kit in order to install it manually ?

Thanks a lot for your time !

Wordpress : 5.8
Pixelgrade Assistant : 1.3.4