Why is oppor9 not displayed and there is no sound when texting?

The notification information can be turned off because the "Do Not Disturb" mode is turned on, or the mute mode is turned on, or the contact has established a second session without being reminded.

1. Check whether mute mode is turned on: setting-sound-mute mode-turn on full mute function;

2. Check whether the phone has turned on the Do Not Disturb mode: Set-Do Not Disturb mode;

3. Has the mobile phone turned off the switch of the notification center: Settings-Notification Center-Information-Allow notification, status bar display, and screen lock display (at present, only ColorOS 2. 1 system has this function);

4. Whether to turn off information notification in mobile phone information settings: information-settings-information notification;

5. Check whether the contacts on the mobile phone are open. No reminder in this session: contact person-contact information-no reminder in this session.