I am having trouble getting the Pay with Amazon IPN working. I have followed the instructions here to setup the endpoints correctly. When I access the endpoint http://example.com/test/testamazon.cfm I get a response of 200. When the Amazon Simple Notification Service Agent tries to make the POST request to the end point it returns a 403.
Some of the troubleshooting I have done is to capture the POST request and use Postman to send a POST request to the endpoint with all the headers (minus the POST body) and it will return 200. I am wondering if there is something inside the POST body that is causing the 403.
I have tried searching for similar issues but the issues I find are related to the verification of the request after it is received to ensure it is signed correctly. I am not to that point yet, I am just writing a phrase to a file so I can see if the request was successful.
Below is a snippet of the access log where it is being denied.
other_vhosts_access.log:example.com:443 10.0.0.84 - - [23/Mar/2017:08:13:27 -0500] "POST /test/testamazon.cfm HTTP/1.1" 403 1150 "-" "Amazon Simple Notification Service Agent"