So I've tried purchasing AMEX gift cards using my SPG AMEX card, BA Chase Visa card, and AMEX Platinum card using the shipping option. My order always completes on the site, however, a few minutes later, I get e-mail message:
Dear Customer,
Thank you for placing your order with American Express Gift Cards. Unfortunately, we cannot fulfill order #10101652 at this time.
Your order was not fulfilled for the following reasons: We could not verify your order information and cannot approve your order at this time.
If you have any questions about this Gift Card order you may call us at 866-268-0582 and reference order #10101652. If you feel that this was caused in error, please contact your credit card issuer to validate your billing address and card security code information. Afterwards, please resubmit your Gift Card order.
We apologize for any inconvenience and look forward to servicing you again in the future.
Sincerely,
American Express Customer Service
After calling customer service, they ask for my order number, mailing address, tell me wait for a few minutes. Then they come back to me saying that each order is subject to review and I should resubmit the order.
After the third time, I demanded an escalation and wanted the question what specifics are causing the rejection so I can purchase the cards successfully. They said they'll call me back when they figure out the issue. I'll give them the weekend to get back to me.
Has anyone experienced this and figured out the cause?

Customer support was absolutely useless.
- Pat