Why can’t l receive message notifications after locking the screen?

To troubleshoot phone settings:

1. “Enable push notification switch.”
2. “Allow background wake-up’
3. “Auto-start app”
4. “Disable background refresh in low battery optimization.”
5. “Automatically close messages when ‘Do NotDisturb’ is enabled.”
6. “Reduce push notifications during sleep mode.”
7. “Optimize network when the screen is off: Automatically disconnect network and background functions when the screen is off.

These settings are generally similar across most Android phones.