If you need to chnage IPN Url make sure that it is still turned on check from History>IPN History and turn it on.
IPN can be enabled in one of 2 ways.
In the PayPal account Profile
Passing an IPN URL as a parameter in an API call or button code.
To enable IPN in your account profile follow these steps:
- Log into your account at https://www.paypal.com
- Click on the Profile
- subtab In "My selling tools" click Update in the Instant Payment Notifications section.
- Click the Edit button or Choose IPN settings
- Enter your IPN URL in the Notification URL field Make sure the radio button for 'Receive IPN messages (Enabled)' is selected
- Click Save
IPN can be enabled directly in this section of the account: https://www.paypal.com/ie/cgi-bin/webscr?cmd=_profile-ipn-notify-edit (access requires login)
To pass an IPN URL as a code-level parameter you should refer to the documentation of the feature you are implementing. Typically the API variable you would pass is 'NotifyURL' but it can differ based on the API call, if the API is Name-Value-Pair (NVP) or SOAP format or if you are using non-hosted PayPal Standard button code. For standard buttons the variable is "notify_url".
This profile setting is frequently overridden by shopping carts. Still, IPN should be enabled in the account.