Transaction fails, on resubmit user gets "Duplicate transaction" error message

I am using eCart6, Authorize.net

I had several complaints of this, tried to recreate the issue by entering false CC, Exp date, CVV, etc, no luck. I found that there was an issue with my clients CC clearing company, and that any transaction using an AMEX was returning "General Error" at Authorize.net.

I have since removed AMEX from the credit card dropdown, but wanted to know why clients would receive a duplicate transaction error message when the transaction failed, and was not recorded to my database either?

even though the transaction failed, Authorize.net would heave still recorded it, authorize.net wont allow the transaction to be resent even it fails the first time.

I'm seeing this a little more often now with other card types. Is there a way to recycle the session, or somehow allow the user to resubmit with updated payment info?

you could edit the code to use the time stamp for the transaction id instead of the session_id:

on the confirm page, change:
$AuthNet_required[0][$nextIndex] = "x_invoice_num";
$AuthNet_required[1][$nextIndex] = "".session_id() ."";

to:
$AuthNet_required[0][$nextIndex] = "x_invoice_num";
$AuthNet_required[1][$nextIndex] = "".time() ."";