Paypal Checkout Problem

Hello there,
I am using the proteo theme and also your “Yith Paypal Express Checkout” plugin. Some weeks ago everything worked fine, but now the paypal payment method isn’t shown at the checkout. When I enable the paypal payment method also on the cart page, it gets shown, but on the checkout page it don’t get shown. Is this a problem of your plugin or of the theme? How can I fix this problem?

Thanks in advance,
PJ

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