Guidance for Changing Xiaomi's Notification Settings
1. No Sounds, Vibration, or Toasts for New Messages
1. Open Futubull > Message > Settings > Notifications > System Notifications
1.2 Open Notifications. Make sure Show notifications is on. Check these settings in turn: Allow floating notifications, Allow Lock screen notifications, Allow playing sound, and Allow vibration.
1.3 Tap all the Notification Categories in turn. Check the following settings: Show notifications, Allow floating notifications, Sound, Vibration, and On the Lock screen
2. Can't Receive New Messages or Messages Delay
2.1 Open Futubull > Message > Settings > Notifications > System Notifications
2.2 Turn on Autostart. Tap Battery saver and choose No restrictions.