Apps closing automatically saying draining your battery

[LankaSri]

I am using Huawei Y5 lite (DRA-LX5; Android 8.1).
I cant using Music app, VPN apps, Games more than 2 or 3 mintues since said apps close automatically with a notification from Android System saying "<appname> draining your battery" .
Please help me to solve this issue and let me know if you need any other info. about my device.

 

[mikedt]

Some Huaweis with EMUI have a rather nasty and over aggressive task killer thing called "Optimiser", check its settings, and make sure it's off.

Also try going into More Battery Settings, and check the options the for app power management etc.

 

[LankaSri]

Some Huaweis with EMUI have a rather nasty and over aggressive task killer thing called "Optimiser", check its settings, and make sure it's off.

Also try going into More Battery Settings, and check the options the for app power management etc.

There is no option in Battery Settings to disable the auto killing apps.
Is "Optimiser" an app?