Reply To: Payment Notifications and Payment not updating in plugin with error email 302

My paypal account settings have IPN switched on and the url entered. I run test payments in sandbox mode and the reservation is created but stays in pending status and payment total is not updated. When I go into the Paypal IPN history page it says “No IPN messages were found”. Is this because it is in sandbox mode? or should the IPN be working already in sandbox mode?