Not working

Among the ten trials, only one worked. In the other nine ones, I set the time and pressed the "sleep" button; but when the set time came, my mac did NOT wake up. As instructed by the app, I do not have passcode for my laptop.

However, when I turned on the mac, the alarm started to ring! Really? Whats the use of alarm clock if I need to turn it on at the time I want to wake up?

One star is for the customizable ringtones.

OopsOwl about Wake Up Time Pro - Alarm Clock