Plugin error

I am trying to use the bol.com products widget. But when I attempt to add it to a page the popup menu reads the following error message:
Not Found

The requested URL /wp-content/plugins/bolcom-partnerprogramma-wordpress-plugin/src/ajax/popup/undefined.php was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

When I try to use the widget from the Display – Widgets menu it does work, but the same widget then appears on every page. I would like to be able to show different products on each page. Please help.

https://wordpress.org/plugins/bolcom-partnerprogramma-wordpress-plugin/