AmEx Offers 2,000 Membership Rewards® points when you spend $50+ at Amazon.com (Select Cardholders)

http://www.amexoffers.com/ is offering select American Express Cardholders: 2,000 Membership Rewards® points when you spend $50+ at Amazon.com
"Enrollment opens on 4/3/2018 and continues until 5/31/2018. Must first add offer to Card and use the same Card to redeem. Only U.S.-issued American Express® Cards that are enrolled in the Membership Rewards® program at the time of purchase are eligible."
Note: I have a platinum card and was eligible.