Push initialization Invalid_Sender Error


I am currently facing an error while initializing the ionic push service.
I used the Ionic Full Setup tutorial to set up the app and gcm service.

Then I started the app, looked for the logs and found this:

V/PushPlugin(25864): execute: action=init
V/PushPlugin(25864): execute: data=[{“android”:{“senderID”:“AIzaSyB2p-djvuxxxxxKk6uGY9JINKFRhWX0qlw”}}]
V/PushPlugin(25864): execute: jo={“senderID”:“AIzaSyB2p-djvuxxxxxKk6uGY9JINKFRhWX0qlw”}
V/PushPlugin(25864): execute: senderID=AIzaSyB2p-djvuxxxxxKk6uGY9JINKFRhWX0qlw
E/PushPlugin(25864): execute: Got JSON Exception INVALID_SENDER

I doublechecked the gcm key and project number, everything looks correct.

Does anyone have an idea what could be wrong here?

Thanks in advance!