Does not work sometimes

Its not the first time but sometimes the alarm wont go off. Its not even in the history or itll go off when I open it app (after the alarm should have gone off hours ago) and itll start ringing. Ive used this alarm for years now and really dont want to change it so really hoping this problem is solved soon.

Aaronchew97 about AlarmMon ( alarm clock ), v3.1.7