Originally Posted by
GateGuardian
Have no received any promo and got an error when I tried to register.

I've had the same problem since the promotion started but forgot about it - I often get errors if the promotion is new. I was reminded of it today, still got the error, called Marriott Rewards customer service. They said some percentage of accounts have this issue and retroactively registered me for the promotion effective the promotion start date, and it should take effect within 24 hours.