Paypal error

Hi there! (again)

I use Paypal for my site(s) and have been for some time without any problems. But, suddenly, I'm getting an error when trying to place an order on my site: once I have clicked 'Paypal' and 'continue' it says:

"There was a problem connecting to PayPal to setup your purchase. Please try again."

I have checked my settings in the shop as well as my account at PayPal, and all seems fine. (It should be fine because I haven't changed anything).
Anyone have an idea what the problem might be?

Best regards,