The default cluster for OpenAM push notification service us-west-1 however currently the default cluster is us-east-1 from backstage, and the initial configuration of the service does not make you select the cluster.
1. Change default cluster for OpenAM
2. Change default cluster for Backstage
Above are quick fixes.
3. Using the APNS and GCN endpoints as part of the url they contain the cluster location as this is a fixed format they could be deconstructed and used to define the cluster for the service.
This will remove the chance of human error.