Microsoft Teams Android app problem, need help

Hello, sir my name is Rajrup Das and sir i am using android teams android application but my experience with Android application is absolute not good.
Sir the main problem i am facing is background running issues.
Sir Teams android application won't running in background, i have tried everything to troubleshoot the problem but nope nothing happened
Actually as soon as i close the application the application force stopped itself automatically, and i don't know why
I hve formatted my ohone two times wiped all data but nothing happend
Yesterday this application received the upddate latest one 1416/1.0.0.2020091301
But nope nothing changed
Same background running issue and application goes to deep sleep after closing the application
Which is a bit weird it have to run in background
I enabled all the permission all battery optimization things have turned off for Teams application
But nope nothing
Where is the problem?
I am using an Oppo A5s Device running on Android 8.1 oreo, it have 3 GB RAM from there 1.46GB free to use and, 32 GB storage and there almost 18 GB free to use
But why i am facing this type of issue?
Can you please help me and fix my problem?
Actually my college classes and online classes held here and also i use that application to meet with my family members
But am missing important notifications, am getting let to join classes,
I am attaching a screen recording video, for your ease, if you look closely you will find that the application when ever closes it goes for deep sleep,
"Look force stop option carefully"
Please help me and fix my problem, am seriously in trouble, begging for help
Please see my post and see the video and please help me
If you need more information feel free to email me
But please help me to figure out
Thank you very much