When paying with IDEAL it is necessary that you first select PAYPAL (you do not need an account!). Then, after entering your address, you can select IDEAL at the bottom of the page and pay for your order.
Unfortunately, the plugin only works when you access the website (www.eentjevanmargo.nl) via your browser, due to an error it is not possible to order via instagram/facebook or google (android) on the website.
Even with an apple (ios), it is only possible if you have come to the website via a browser. Jimdo is aware of this problem and is looking for a solution with paypal/ideal.