Lockscreen does not unlock on alarm
On Xiaomi/MIUI, you need to grant special permission to Sleep as Android so that it may unlock your screen during alarm.
Go to System Settings → Permissions → Advanced Permissions → select Sleep app and give it permission to access Lockscreen.
When alarm goes off, it does not disable the lockscreen and you have to manually unlock the device to tap snooze or dismiss.
You may have Sleep as Android enabled under Border lights. This causes the alarm popup to not display over the lockscreen, as the notification is being shown as a light around the edge of the screen.
Disable Border lights for Sleep as Android in your device’s settings.
Tags: alarm, lockscreen, xiaomi, miui, samsung