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.