In case your Gnowbe app is not working as expected, one of the first things you should try is to close your Gnowbe app and open again.
Here is how to do it.
For iPhone 8 and earlier
Ensure that your iPhone is unlocked. Double click your home button and you will see a cascading view of all the apps currently open on your phone (the apps are open in the background, they may consume battery and/or data). Touch the Gnowbe app and swipe upwards to close it. Double click the home button again to see your home screen. Find the Gnowbe icon and open Gnowbe again.
For iPhone X and later
Ensure that your iPhone is unlocked. Swipe up from the bottom and you will see a cascading view of all the apps currently open on your phone (the apps are open in the background, they may consume battery and/or data). Touch the Gnowbe app and swipe upwards to close it. Tap anywhere outside the outline of an app to resume the home screen. Find the Gnowbe icon and open Gnowbe again.
For Android
Launch the recent applications menu (this differs from device to device). Find Gnowbe app and swipe up to kill the app. Tap anywhere outside the outline of an app to resume the home screen. Find the Gnowbe icon and open Gnowbe again.
What else you can do?
In case the above method does not work for you, please check that you have a working internet connection. You can check this by opening your mobile phone browser and opening a web page that you have not opened recently.