Hi!
Usually, it happens when the installation is not being created properly.
Here are the required fields for each platform:
For android devices, the fields "GCMSenderId" and "DeviceToken".
For iOS devices, the fields "AppIdentifier" and "DeviceToken"
These fields are filled automatically when the user installs the app.
In case they are being filled, please, make sure that you are following all the steps of our guides and send me your app ID and we'll check if there's anything on our end that can help you to solve it.
Regards,
Charles Ramos