I have posted on here about my problems booking with Emirates. Same issue: claims my CC was declined, but EK made no request to my card. I just gave up and bought the tickets on Expedia.

Dear EK, please fix this.

It's still crashing at the Mastercard secure payment bit.

But on the positive side, at least you have then made the booking, been able to review all flight choices leading up to your booking, and have got your booking into their system. And almost certainly they have got your credit card debit through to Mastercard and it has occurred.

Now you just need to confirm things and get your booking reference. You call Emirates (I use the main Dubai call centre which runs 24/7, and has nice English speaking operators) with the flight number, time, and my name, and they will go into the system and retrieve the booking and give you the booking reference and send you a confirming e-mail.

A bit slow and clunky, but when you are on the road, in backward_holeville_south, it works for me.
Their number is +971 600 555555.

I've also faced this the 2 times I tried to buy a flight on the EK website. Credit card always gets declined even though I've called the credit card company to clear it. Apparently per the call center, the EK website also has a 3 strike limit to credit cards getting declined and only gets reset after 24 hours.

EK seriously do something about this. If I end up calling the call center, please take my $$$. I ended up booking on Expedia and if there were other airlines, I would NOT hesitate to book with them instead of EK.

Facing same problem. While making payment online I donot get Mastercard Securecode page neither Visa verifed page. Finally getting below message everytime trying to book the ticket.
"Unfortunately your booking has not been successful due to a problem authorising your payment. This may be due to the incorrect details being entered, or due to the incorrect MasterCard SecureCode or Verified by Visa password being entered, a restriction from your bank on the value of an internet purchase with a merchant located in the UAE, or other reason. Please check with your card issuer or payment provider, or try again using another payment method". I hope Emirates realises this problem.
I contacted my card Issuer and they said no request from EK and neither have denied the payment request.

I had the same issue. When called them at +971 600 555555, they told me that if the booking is made on online, payment has to be made immediately. If not, you either have to call above number and make the payment or go to the Emirates ticketing center if you have one near by.

I've tried Safari, Chrome and Firefox and different cards over a 48 hour period but cannot make an online booking with Emirates. They must be losing customers left right and centre over this. I'm a Skywards member and they have all my details yet still don't seem to want my custom. This is my tenth trip with them to Saigon - or it would have been. Am now having to look elsewhere.
The points aren't worth much anyway so it's hardly a big deal.