I got a response back from my follow up email to Amazon and they just said the following. I guess based on the information we've gotten back from them you should try again, and if the transaction fails again, you might want to give a quick call to the bank to make sure the transaction didn't set off some fraud protection trigger:
Greetings from Amazon Payments.
We have reviewed your Amazon Payments account and found no issues with your account. Due to technical glitches sometimes few transactions get failed.
Please request your customers to re-initiate a transaction.