Meanwhile I received an answer from Booking.com. Friendly lady. She said it has to do with the restrictions I put for my house. like f.e. strong restrictions instead of flexibel ones, pre-payment, ... New members must set flexible restrictions for their ad to show on the Booking.com site and payment upon arrival. Only after 25 bookings, you can change your restrictions to less flexible ones. As English is not my mother tongue, this is what I understood. I changed everything (not to my liking) and apparently it works now. Thanks all for your help.
Meanwhile I received an answer from Booking.com. Friendly lady. She said it has to do with the restrictions I put for my house. like f.e. strong restrictions instead of flexibel ones, pre-payment, ... New members must set flexible restrictions for their ad to show on the Booking.com site and payment upon arrival. Only after 25 bookings, you can change your restrictions to less flexible ones. As English is not my mother tongue, this is what I understood. I changed everything (not to my liking) and apparently it works now. Thanks all for your help.