Ionic Push GCM_UNKNOWN

It’s been all day i’m struggling with this.

I’ve followed all the new documentation for the Push Service, as long for registering users.

First of all, i can’t see any user in my ionic.io dashboard of the app, even if my app get a Registered Token when using push.register()

Then, when i try to send a Push notification to specific tokens, all of them got a GCM_UNKNOWN error.

Any ideas?

Thank you in advance