What happened?

I use this app for about 2 yrs, and really like it more than any other I tried before. But in the past month its not working as it was. Alarm sometimes doesnt go on, and its not always register my sleep. Sometimes its no data whatsoever, almost like I didnt put on. What happen? Why is it stop working?

Sister from NY about Sleep Meister Lite, v1.12.23