Error on setup: "failed open com status: (-3)"

I just received the Conbee II but haven’t been able to make it work.
I plugged it to my raspberry pi (it’s a headless setup) and launched the following command:
/usr/bin/deCONZ --platform minimal --dev=/dev/ttyAMA0 --auto-connect=1 --http-port=8080 --ws-po
rt=8081 --appdata=/home/pi/deconz --dbg-info=2 --dbg-error=2

But I have the following logs on a loop:
11:45:16:998 GW firmware update select /dev/ttyAMA0 device
11:45:16:999 GW update firmware not found:
11:45:17:408 wait reconnect 2 seconds
11:45:17:908 failed to reconnect to network try=4
11:45:18:408 wait reconnect 1 seconds
11:45:18:497 COM: /dev/ttyAMA0 : (0x0000/0x0000)
11:45:18:499 dev /dev/ttyAMA0
11:45:18:500 COM: /dev/ttyAMA0 / serialno: , RaspBee
11:45:18:500 failed open com status: (-3), path: /dev/ttyAMA0

Am I missing something?
I am able to select the gateway in the app but it doesn’t detect anything, even a switch that is just near it.

My bad, I apparently enabled login shell accessible over serial but not enable serial port hardware.