"Upsell Items" can not be exported to Booking.com.
If required you can enter extras and fees
can directly in Booking.com.
*Booking.com: Ask Booking.com to remove the guaranteed allotment
'''Rate is not active'''
You do not have an active Booking.com rate id with this number. Please double check your rates and daily prices and select a valid Booking.com rate id from the list in 'get codes'. You can only send prices for active Booking.com rate codes. You will see your active rate codes when you click on "Get Codes". Make sure you only map these rates in you channel manager settings, daily prices and rates.