Cannot connect to Nuki Door Sensor

I’ve just bought a Nuki Smart Lock, Bridge and Door sensor and unfortunately, I am not able to set the door sensor up. As per instructions in the app, I put it in maintenance mode, it starts pairing but fails after a while spitting out the below message. Does anyone know why it’s doing that and how can it be fixed?

Please contact our support via the Nuki App (Menu > Help > Contact Customer Support) as this is an individual problem and might require sharing logs and other sensitive data.