I wasn’t able to authenticate because of this bug. Thanks @vlagged I installed librespot 0.5.0. With this version, password authentication is disabled. So I ran this command:
librespot --cache /home/defaultuser/.cache/librespot --name Sailfish --bitrate 320 --initial-volume 80 --device-type smartphone --backend pulseaudio -j
An URL is generated allowing to authenticating using OAuth. Once that done and credentials.json is created with all data, I had to move to the right folder (/home/defaultuser/.cache/librespot) and hutspot recognized correctly my device 