I am using Vivo 1610

Step 1: Go to Settings and tap on the Status bar and notifications.

Step 2: Tap on Manage Notifications

Step 3: Scroll down and tap on Skooly app

Step 4: Click on Allow Notification to turn it on

Turn off Data Saver:

Go to settings -> Mobile Network -> Scroll down to bottom -> Tap Data Saving mode -> Turn it off, if turned on.