Hi I can't get the APP Notification work on my Mi 6 (MIUI 9 Global). When I do press the test button it works but when I receive message I cant see any notifications on my Mi Band 2. I am using the PRO version .
I don't know if you solved this but try set your phone as is said in MIUI instruction in help section, and then look in notification your settings.
I had same issue. In my case I have selected to notify me only when screen in phone is turned off, and I saw that each time I got new notification, automatically screen was turning on - that was the reason notifications stopped working, but the test was OK.
Just uncheck all "ignore all notifications when something" and should be ok. Hope this helps.