Issue Description
When using paypal sandbox and you want to update the IPN notification URL.
Sandbox does not reflect Live, the IPN URL is not in the same place.
How to Fix the Issue
https://www.sandbox.paypal.com/myaccount/home
Top right, settings wheel.
Seller Preferences (bottom left)
Takes you to: https://www.sandbox.paypal.com/uk/cgi-bin/webscr?cmd=_profile-display-handler&tab_id=SELLER_PREFERENCES
Click Instant Payment Notification -> Updates
Takes you to: https://www.sandbox.paypal.com/cgi-bin/customerprofileweb?cmd=_profile-ipn-notify