VIMP uses the Instant Payment Notification (IPN) by Paypal to be notified about already made payments. Thus, Instant Payment Notification (IPN) has to be activated:
- Login at https://www.paypal.com with your seller account
- Open your profile and choose "My selling tools" on the left
- Click "Update" next to "Instant payment notifications"
- and next click the button "Choose IPN Settings"
- Now enable: "Receive IPN messages (Enabled)" and add your VIMP-URL as the "Notification URL" like this: "http://myvimpurl.tld/paypalFrontend/IpnListener"
- and Save.