'''Did not set Close Room 'XY for Rate Category 'ZZ' because of remaining Minimum Contracted Rooms on dates.....'''
You have guaranteed and to have a minimum number of rooms to sell on Booking.com but the channel manager is sending a lower quantity than contracted.
You *Make sure you have two options:valid rates for the mentioned dates and no bookings from other sources
*Beds24: change your inventory to send the minimum contracted rooms you have guaranteed Booking.com
*Booking.com: Ask Booking.com to remove the minimum contracted rooms