MIDI implementation on the QC is currently very limited. You can have an external MIDI Clock route through the QC by enabling MIDI Thru. However, the QC does not respond to any incoming MIDI messages, nor are any of the MIDI CC or PC messages saved with your QC patches transmitted.
Alternatively, you can switch MIDI Thru off and turn MIDI Clock Out on, which will allow you to tap on your QC and have this tempo sent to your downstream devices, as well as transmit any CC and PC messages saved in your patches, but you will be unable to sync to an external MIDI Clock.