Push notification not being sent from loopback

I have used the loopback sample application "loopback-3.x" given on:https://github.com/strongloop/loopback-example-push. The correct server key was given in config, then created an application and registered a device with that application. Then I tried sending a push notification with "notifyById" method. The console shows a succes message like:

loopback:component:push:provider:gcm Sending message to ["devicetokengiven"]: {"params":{"timeToLive":3600,"data":{"message":"sfwsed","messageFrom":"sdefsdf","badge":2}}}
loopback:component:push:provider:gcm GCM result: {"multicast_id":multicast_id,"success":1,"failure":0,"canonical_ids":0,"results":[{"message_id":"0:23423555466%24324434354"}]}

It seems to be a success, but the device doesnt get any push notification. What could be the issue? Any help would be appreciated! Thanks!

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