Log into app.zeevou.com and click on the settings gear icon and select Preferences. Then, you will be redirected to your Organisation Configuration. Under Booking Config, you need to make sure the time you enter in the fields follows the below order:
earliest possible <earliest free <latest free <latest possible
Please note that 23:00:00, 23:30, 23:59 are considered the last hours of a day, while 00:00:00, and 00:30:00 are considered the beginning hours of a day.