If you are using a Huawei phone, you might face some issue with the Alert feature. To save power consumption, Huawei may force some background tasks to close causing the Alert feature to malfunction. In order to prevent this, you need to turn off the “Auto Manage App Launch” option in your Huawei phone.
To turn off the “Auto Manage App Launch” option, go to the Phone Settings screen. Click on the App to go to the App settings screen.
On the App settings screen, tap on “App launch” link to go to the App launch settings screen.
On the App launch settings screen, scroll down to look for SingBUS app. Turn off the switch to disable auto management for SingBUS app.
Make sure all switches are turn on in the Manage manually dialog. Tap on the OK button to complete.
This will disable the “Auto Manage App Launch” option to prevent the alert task from closing when your phone goes to sleep.