PayPal IPN Stopped Working 422 Error

I was using PayPal Web Standard and receiving IPN notices from my payments perfectly fine for a couple months. Earlier this week it stop开发者_如何学JAVAped working. I have not changed any of the code for the function in sometime. I figured I would try here as a last resort as PayPal support pretty much just said, "not our problem".

I'm using ruby 1.8.7 and rails 2.3.9. I more or less just followed step by step the railscasts for setting up PayPal standard. http://railscasts.com/episodes/archive?search=paypal

Looking through the logs on the server. I am getting 422 errors with error ActionController::InvalidAuthenticityToken.

I'm already using: protect_from_forgery :except => [:paypal_IPN]

It is not getting to the paypal_ipn function

Any help is appreciated.

Turns out it was a bonehead mistake on my end. The route that received the IPNs was setup to receive get requests and not post request. Changing the method in my routes file to use post fixed the issue. This doesn't explain why it was working for the few months prior.