Hummingbird pwhash hanging

[cdupont]

Hello, I just installed the Debian distribution on my Ubuntu 16.04:

sudo dpkg -i hummingbird_0.8.1.0-1_amd64.deb 
sudo cp /usr/share/hummingbird/resources/principals/mqtt-default.yml /etc/hummingbird/principals/
sudo hummingbird pwhash

But nothing happens next. It hangs on the last command forever.