I'm trying to test the subscription payment process using PayPal Express Gateway but ran into an error on the PayPal sandbox website. I logged in using a test sandbox PayPal user and this page: https://www.sandbox.paypal.com/uk/cgi-bin/webscr?cmd=_ ........
The link you have used to enter the PayPal system is invalid. Please review the link and try again.
My Membership gateway settings are:
PayPal Site United Kingdom
Paypal Currency GBP
PayPal mode - Test mode (sandbox)
Left the buttons with their default urls.
(I changed the PayPal site to United States - which resulted in the same error)
I'm not sure what I'm doing wrong?