valid AMEX rejected thru Authorize.net (SIM)

Setting up a web store for my client who is using latest version of Zencart v 1.3.8 and the Authorize.net (SIM) payment module.

The module is setup and running in production mode. We tested the module and made payments with all cards and they worked successfully. All except one, American Express (AMEX).

For some reason all valid AMEX cards are being declined? At first I thought it was AuthNet's issue to resolve so the client contacted them and they set everything up. Secondly the client ran a test process on a valid card directly through AuthNet and it went through just fine. So clearly AuthNet can process their card through their account ok. Tested it again through Zencart but with no change.

Anyone have any ideas?

The webstore is using SSL but the AuthNet module is setup as SIM not AIM. Would this resolve the problem perheps? What is the difference between SIM and AIM anyway?

Thanks in advance for your help!

Shaun

Did you enable Amex in your Zen Cart admin? Admin->Configuration->Credit Cards

BEatMaKeR:

The webstore is using SSL but the AuthNet module is setup as SIM not AIM. Would this resolve the problem perheps? What is the difference between SIM and AIM anyway?
I would strongly recommend AIM over SIM. It's more secure, and more reliable, and gives the shopper a more consistent experience since they never leave your site to make payment.

AIM module setup instructions: https://www.zen-cart.com/tutorials/index.php?article=373

Nope you know what I certainly didn't enable AMEX in the cart separate from the payment module. I wasn't aware I needed to but thanks Doc! :)

Yes they have an SSL already paid for so I'll try to switch them over to AIM today. The only thing that scares me about the AIM is the whole "**CURL is required **and MUST be compiled with SSL support into PHP by your hosting company" thing. What is that all about? Sounds like a nightmare to setup?

It shouldn't be a nightmare ... at least not for you. It's basic configuration, but not all hosts are created equal, and many cheaper hosts don't provide all the suitable services for running an advanced website such as Zen Cart.