When you select the "Print Registration Card" button for a particular booking, sometimes, the registration card will show an empty white page. Why?
This happens when there is no companion assigned to the booking. This happens often for multiple room bookings as the creator can be physically only in one room.
How to solve this?
Simply open the booking, go to the "groups" tab and add at least 1 customer as a companion to the group. Then try to reprint the registration card... and it should work.
Note: See attached 2 screenshots, which help explain it further.