Notifications can't work on Huawei and Xiaomi Android phones
Notfications can't be received when Teams is in the background, e.g. on Xiaomi 9 with MIUI 10.2.33. When Teams is in the foreground, notifications can be received.
All notification and application settings are switched on.
Here are all phone setting screenshots and application logs. When you reiview logs, please note there should be notifications in around every 5 mintutes from 12:00.
Dustin Dong commented
It is a serious bug for Teams - our company are all using Teams but it seems most Android phones can work. We can't use Teams without notifications, please.