"Pay now" button for paypal payments

Hi,

Unfortunately I have another problem.
When I do the order process with payment method paypal/credit card unti the end, the window appears where it says "If you are not redirected to that page, press the button below" and there is the "pay now" button. But when I am impatient or when I overread what it says above (which can easily happen because it looks the message is very decent), thus when I klick on that button, the paypal site never opens, it is endlessly loading.
When I don't press the button and simply wait, it works fine.

What could be the cause?

Thank you,

Chantal