Error processing credit card, but payment appears at Authorize.net

I'm trying to get Zen Cart ready to go live for the first time and have tried posting a payment through the Authorize.net SIM module.

I tried with an actual credit card from the shopping cart checkout, and it bounces back to the Payment Information screen with the message "There has been an error processing your credit card. Please try again."

When I log into Authorize.net, however, it says the payment has actually gone through. And an email receipt goes to me indicating that it went through.

I was getting the same errors before taking it out of test mode, and thought it was related to being in test mode, so I turned off test mode, but that made no difference.

This is different from other threads I've found on the forum, as the payment goes through but the message to the user is that it has not.

PHP v5.4.29
MySQL 5.5.37-log

What should I be looking for?

Thanks.

You could try enabling the payment method's debug mode. I think (but do not know) that the debug might give some details since "there has been an error ..." is pretty vague.

I did have debug mode on. I looked further into the results on there.

I see these 2 results.
[x_response_reason_text] => This transaction has been approved.
[HashMatchStatus] => FAIL

I do have a hash set up in ZenCart for the Authorize.net module. What is this hash supposed to match somewhere else?

The hash should match the hash value that you've set in your authorize.net merchant account. Try googling "authorize.net hash value".

Thank you. That took care of that problem. Now on to fixing other problems.

See this FAQ article on correctly configuring the module: http://www.zen-cart.com/content.php?303-how-to-set-up-the-authorizenet-sim-payment-module
That same link is in the help text in your Admin, in the module configuration area, for easy reference.

I am getting the same error message as shfscotte.
I have confirmed my Login ID, Transaction Key and MD5 Hash with Authorize.net
I am set in Test mode using Authorization type "capture" and have tried setting the Gateway Mode from "onsite" to "offsite".
I have the debug mode set to Log and Email but the email doesn't offer much of an explanation.
I could not find a folder in the Authorize.net module for logs like the one in PayPal so I am not certain where the log is stored.
But I am trying to set up (SIM)

But someone at Authorize.net had suggested I try setting up (AIM) as well to see it I had the same issue.
Do these use the same credentials or do you have to generate a set for each (SIM) and (AIM)?

SIM setup: http://www.zen-cart.com/content.php?303-how-to-set-up-the-authorizenet-sim-payment-module
AIM setup: http://www.zen-cart.com/content.php?291-how-to-set-up-the-authorizenet-aim-payment-module

Logs will be in the /logs folder