Kerlink iFemtocell - connect to TTN?

Hi guys
Here i am trying to setup a ifemtocell kerlink gateway to TTN.
I register the gateway, but get the No connected message.
I have not registered or joined motes at this point.

The “Gateway Key” is used for Semtech Packet Forward or must be ignored and only is used for TTN Packet Forward ?

Thanks in advance.

Hugo