[Android Central Question]

Hi, am new on this group.

I've purchased Vivo V9 a month back and I like this model. But, I am facing notifications issue in my Vivo V9.

Thing is, when I got notifications on Whatsapp, G-Mail, Missed Calls, Messages etc. so all of these notifications doesn't always shows up in the locked screen/notification tray etc. I am a freelancer and it's very important for me to keeping eye on my G-Mail, UpWork App (My Work Related App), Parallel Space (Using one useful clone app on this), Skype etc. But most of the times, I don't get any notifications on the locked screen even sometimes on the notification tray. I've checked with all the settings such as each app's notifications/permissions settings, general notification settings etc. everything. Even, restored my phone for two times. But, I always missed few of my important notifications. i.e. I've setup Whatsapp to show all the notifications one the locked screen, pop-up, notification tray etc. but whenever i got message on Whatsapp, it makes sound, popup appeared, showed in notification tray but doesn't show in locked screen.
Moreover, sometimes the notifications doesn't shows up even on a notifications tray.

I wanted to know that is somebody facing this kind of issue on this model? If so, what did you do to resolve this? Or, if someone has idea of all the possible reasons for this issue?

Thanks!