CTA Certification schedule

Hi folks, 

I would like to take the CTA Exam ASAP, but when I try to schedule it, I get the error message, that I have to enter a valid voucher or promotion code. I don't have anything like that.

Is it because I have to prove that I am already CTD? 

Anybody there, who can confirm, that I have to enter a valid voucher or promo code?

I think that this is the only certification that you can take at Pearson Vue and that has an entry requirement.

Thanks in advance

Michael