I'm trying to book a flight in business for June 2024 from Chicago (ORD) to Madrid (MAD) with Avios. No matter how many times I change passengers, departure dates, departure location, etc, it always says "not available" for business class. I find it hard to believe that every single business seat would be booked 6 months out. Only when I change to paying with cash does business class availability appear. Is there something I am doing wrong?