If you are on a data network, verify that the Wi-Fi option is ON and that location services are enabled.
If you built your application prior to creating the geofence or the communication, the location and contextual content updates may not have been received by your device yet. Location and contextual content updates are updated overnight on Android™ devices and within 24 hours on iOS devices.
For testing purposes you can reinstall the application to start receiving events immediately.
If you create the geofence or the communication before you build your application, you should start receiving events immediately.
You may already be inside the geofence and thus have not triggered an entry or exit event