Cant connect my FB page to my WooCommerce

I want to connect my webshop to FB. Every time I connect the store I get this error on my WordPress: Could not retrieve Facebook Business Extension System User. While I completed the integration process on Facebook and Facebook said “All done” at the end of the process.

So I went to my Facebook page (https://www.facebook.com/niffostudios) and there I saw my Webstore (www.niffostudios.com) connected to my FB page and I was able to see “Niffo Studios” as store on my Facebook Business page. But the store is “inactive” because there are no products visible on FB. The products in my webshop are imported by Printify (integrated). Could that be the problem? Does anyone know how I can get my products visible on FB?

The page I need help with: [log in to see the link]