Alarm is not working on my phone

[Android Central Question]

So I downloaded an alarm app, and it worked well, until last week, when I got a notification on my status bar instead of the alarm blocking my screen. There was no sound. When i clicked on the notification, then the alarm started to ring, but as I said, only when i clicked on it. So I tought its the apps problem, so I deleted it, but it's still happening on my original alarm.
-Huawei P9 Lite