Payment Notificatoin URL Not Working

[hunzaboy]

Hello There, i have a third party script that needs to be updated when a payment is made..

i have put this in my Payment Received Notification:
http://mydomain.com/notify/?aslam=1&username=%%user_login%%&email=%%user_email%%&test=%%item_number%%

its not working.. however when i manually enter this address in the browser it works and the database is updated.. while after a payment is made nothing happens, I still get the payment email but not the notification ..
Help me out!