I am trying to get eprocessingnetwork working with my zen cart 1.39H

I would prefer to use it with authorize.net AIM module and it sems people have success doing this but I Have not.

I changed the URL to EPNs and it doesn't work I then tried making some changes to code mentioned in other threads and still no luck.

When I try processing I get an error saying the transaction could not be processed for the following reason, but it doesn't give a reason. I do get an email stating I had a declined transaction.

Does anyone have a straight forward step by step on this. THere seems to be very little info on here and it seems to conflict. Numerous people suggesting different code edits