Paypal Payment stuck as pending

Hi again,
in Paypal sandbox mode the test payment after completing the registration form, completes successfully and all paypal emails are received, but on real life purchasing it gets stuck on pending on the admins registration list although the money comes out of the customers paypal account and they receive paypal payment confirmation email. So that means that the customer does not receive notification of completing the registration form, and it is stuck on pending on the plugin on the admins events registration list.
Am i missing something?