I integrated PayPal Button in my website.
When an user select pay with PayPal Button, a PayPal login screen appears. The user login into, select your card, shipping address and click in "continue".
After that, PayPal redirects (using JS) to my callback URL:
In some cases, after redirect, the session is changed. So my PHP script, that handle /paypalbutton/redirect, cant read the cart_id stored in the session.
Any ideas ?