# Paypal ipn issues after upgrade to 4.6.15.

Paypal ipn is failing with 500 after upgrading to 4.6.15 from 4.6.10

The notification url looks correct but isn't working https://www.mysite.com/civicrm/extern/ipn.php?reset=1&contactID=83&contributionID=80&module=contribute

I am using Drupal 7 with Pantheon. I already have implemented this patch https://www.drupal.org/node/2177647

I'm not sure how to further debug this. The extern/ipn.php file hasn't changed from 4.6.10 to 4.6.15. Where else can I look.

Any tips on debugging would be greatly appreciated, thanks.

Why is IPN failing on Pantheon?

Check out CRM-17212: IPN and other scripts break on Pantheon due to session handler although it does look like you have a similar patch in effect. Compare your changes with those merged into the 4.7 branch, or consider trying 4.7.

How do I debug on Pantheon?

On Pantheon hosting, you can inspect your application's error logs in:

logs/php-error.log