Midi clock out is not working

I noticed that my mpc one+ does not send midi clock information from its midi out port.
Despite the fact that I configured it in the MIDI/Sync preferences screen to send out MIDI Clock.
Other midi data like note info etc is sent out properly. What am I missing here? Is this a bug?

Never mind. I forgot to toggle the little sync button next to the output port in the MIDI/sync preferences screen.