Can't set max days to reserve

We just registered our small place and afaik everything is set up correctly. However when I try to test-book it, I can't select more than 3 days in a row. For some reason booking.com thinks that we don't accept more than 3 days. Which is of course not correct. In the support section it's written that there should be a max days that can be reserved inside the calendar view. However I can't find it in any of the subviews, no matter if I check in List or Month. Help?