I am using a paypal subscription button, with server side listener for webhook event notifications still in sandbox mode.
I think everything is fine for every event except for PAYMENT.SALE.COMPLETED. Here I receive the event notification, verify, process and respond with a small html page (some regular description page) with http status 200. When I go back to the paypal developer dashboard I see the event still being PENDING. The exact same event is not being resend, as it would be the case if i would have responded with any other http status code than 2xx.
What is the reason for this PAYMENT.SALE.COMPLETED event always being PENDING. Do I have to take some additional action for this event?