The first step would be to ensure that notifications settings for Tango are enabled inside the Tango app itself!
Open the menu by tapping on your profile and tap on Settings
Choose Notifications and Sounds
Check the options you would like to enable and uncheck to disable.
Still not getting the notifications? Don't worry. Now we check the settings in your Android device.
Slide down the top of the screen and tap the Settings button
Choose Apps & notifications
Tap See All X Apps
Find Tango in the list, and tap on it
Set up your notifications from Tango on this screen
After doing all this, if you are still not receiving notifications, please contact customer support for assistance.