I'm not sure if this is the right place to post this...

Is there a reason that I can't redeem my 2 free award nights (credited when I signed up for the Chase Hyatt Card) for a certain hotel in September? When searching for the hotel in regular reservations, there are standard rooms available for points. However, when searching for the hotel through the Award Nights search, I get the message:

The property or award you have selected is not available for the selected dates indicated. Please contact Gold Passport Customer Service at 1-866-557-6671 or your nearest Worldwide Reservation Center

Is there a reason for this?