GCM to Domoticz lite app

[Kennet]

Hi

I have a Synology NAS running Domoticz 3.8153 and I am trying to push notifications to my android phone.
On the phone I have the domoticz lite app and it connects to the Domoticz server and reads status and that all looks like it is working fine.
But I cannot get Notifications to work. I am trying to use Google Cloud Messaging.

I have Enabled gcm in the settings on the Domoticz server.
On the phone I have pushed the "push your registration id to domoticz" many times. But when I do this nothing happens.

In the "Settings" ->"More options" -> "Mobile devices" the phone is not showing up as I would expect it to.
When I send a test message on the Domoticz server it says message is send but nothing happens on my phone.

Any hints on what may be wrong or suggestions what to try is appreciated.