How to verify on an Android that the Atrivity app has permissions enabled to receive push notifications? 

Share this message to users who have used Atrivity before, or at least to those who ask questions about notifications:

Dear user

Verify that you have enabled permission to show notifications for Atrivity at the operating system level. 

To do this you can go on your mobile device to Settings=>Applications=>Atrivity and check if the permission for notifications is enabled. 

The menus may differ depending on the device, but the options are similar.