Please try the below:
1. Check vibration settings:
Go to Settings > Sound & vibration > Vibration and toggle on Vibrate for Calls and Notification vibration/Touch feedback.
2. Press the volume key to enter the ringtone Volume settings. Click the ringtone icon and check whether the vibration is on.
3. Reboot the phone and try again.
4. Back up all data and restore the phone to factory settings.
If the issue persists, please contact our Customer Support for further assistance.