If you're having issues scheduling a trip, the reason could be that scheduled trips aren't available in the pick-up area.
If this is the case, you'll see an information icon appear next to Today – now beneath Choose when they'll ride. Hovering over the icon should populate a box explaining that scheduled trips aren't available in the pick-up area you selected.
Double-check the pick-up and drop-off addresses. If they're both correct and you can't schedule a trip, you'll need to either: