Configure power manager
On Huawei phones, Hiitmi (as well as other apps) may not be able to run in the background (or when you turn your phone screen off). Huawei has an energy manager app called PowerGenie that kills most apps that are running in the background. You can whitelist Hiitmi in PowerGenie to make it run in the background.
- Go to:
Settings > Battery > App launch -> Select Hiitmi
Read more here: https://dontkillmyapp.com/huawei
Allow notifications
If you don’t see any notification of the app like in the picture, it may be because Huawei requires you to explicitly enable notifications first in order to display them. A notification is needed to allow the Hiitmi to run when the screen is turned off. If not, you can try the following two ways to activate the notifications of Hiitmi:
- Go to:
Settings > Notification > Select Hiitmi
- Turn on Allow notifications
- Turn on Display in status bar
- Turn on Lock screen notifications
2) Go to: Settings > Apps and Notifications > Select Hiitmi
- Tap Settings at the bottom of the screen
- Select Special access
- Select Ignore optimisations
- Change the drop down at the top of the screen to All apps
- Select Hiitmi from the list and tap on Allow
Settings 
Special Acces 
Ignore Optimisations 
Allow Hiitmi