Troubleshooting - The campaign is not playing on one device

Make sure that the device has an internet connection.
Place device in debug mode from the 3 dot menu in the top right.
Go to the settings of the device and check the current date, time and year. Make sure that it is correct. If it is not set it to the correct date.
Try a different WiFi network and wait.
Make sure that the application is updated to the latest version. If it is not, update the app.
Apply all available system updates.
Unassign the device from your position and fixture and enroll it again.
Last resort: Re-install the application or Factory reset the device if it is QR code provisioned android