Using Payeezy -- Can't Get The Orders to Carry Over

To start off, I am very new to Zen Cart. I was trying to set up my Payeezy Web Payment page with Zen Cart, but I keep getting an error message on the Payeezy message side once the order is confirmed in the cart. It simply says "Unable to proceed with payment." I followed the steps of this link provided by Payeezy (later I had a conversation with their tech support, and was informed that the tutorial I used may be out of date, because they haven't updated any of the support pages on the site I was navigating in at least 3 months). Any support would be much appreciated! Please let me know what other information is needed to help resolve this issue. I'm using GoDaddy as my host.

https://firstdataclientsgge4.zendesk.com/entries/23526222-ZenCart-v1-5-x-Integration-Instructions