Doesn't go off if your phone is locked – CARROT Alarm - Talking Alarm Clock Review

I was really excited for this alarm app, I have always been terrible at waking up. But the alarm doesn't go off if your phone is locked. I followed the instructions to have the app open and not in the background when you lock your phone for the night, but the alarm didn't go off until I unlocked my phone 20 minutes after it was supposed to go off. The support section also says to make sure you have notifications on for the app, but it doesn't show up in the notifications settings section. Hope they fix this.
Review by Rabbits & cats on CARROT Alarm - Talking Alarm Clock.