not working / loading

I’m trying your plugin but it’s not working.
When I click edit link in cart, it’s shows very short a loader/spinner and then evertyhing is blank

recording: https://sharing.codeagency.be/50ac84f7ce5a

In console, also an error 500 shows immediately for admin-ajax when I click the edit link
domain/wp-admin/admin-ajax.php 500