Paypal says, use CCREJECT-REFUSED for address1 in credit card detail. https://developer.paypal.com/webapps/developer/docs/classic/express-checkout/ht_ec_fundingfailure10486/
I tried creating new test user (CC credential was automatically created). Login into sandbox and add CC detail I got from first step. I change address line to CCREJECT-REFUSED. Save it. And then tested it, checking out via sandbox. Error 10486 was not triggered.
Any hint?