While working with integrating PayPal with an MVC 3 app hosted on Azure, we just couldn’t get the PayPal IPN notification to work.
We were stuck with the following message!!
IPN delivery failed. Unable to connect to the specified URL. Please verify the URL and try again.
After a lot of brainstorming , tracing, debugging and re-reading the documentation , we realized that the issue was that our website had a custom endpoint of 8080 as against the default 80.
Paypal sends the IPN HttpPost request on port 80 so a request to http://xxx.cloudapp.net:8080/PayPalController/IPin will fail!!.. Ensure you are hosted on port 80!!
Hope this helps a few of you PayPal -Azure devs out there!!!