Nexon keeps saying my address is unconfirmed

When I try to use paypal to buy NX it always says:

The seller of this item requires you to provide a Confirmed Address for delivery. To confirm your address, please add a credit card below.

I haven't changed my address, but I am using a new credit card which is registered to my current address. Any ideas?

I believe it means you need to change your Paypal status to "confirmed".
When you added the new credit card it didn't ask you to confirm it?
If I remember correctly, the "confirmation" process is simply Paypal charging you some low sum ($2 I think?) and crediting it to your paypal account. This tests that your credit card company will honor paypal payments with the billing address you gave them.

I've never had to confirm it before, but I guess I have to do that. Thanks.