Auto sampler in MPC Software not working for AU plug-ins

I've used the MPC Software to auto sample some external synths - this worked.
Then I tried sampling an AU plug-in loaded into the MPC on the first track. I have it selected, I have all the settings as I 'believe' they should be. I checked that the AU was outputting to the Resample L+R, and yet, nothing. I get a click sound once every 6 samples or so, but this does not work and I have zero idea what may be wrong?

Is there some setting related to using AU plug-ins within the MPC Software?
If they play via midi - that should be all that is required right?

Just a note, I am trying to sample an NI Kontakt patch, and i did check the note on/off settings in Kontakt as per this thread:
https://www.mpc-tutor.com/mpc-bible-tut ... tosampler/

However, I just can't get it to work. I may have to see if I can trigger the plug-in as if it were an external source somehow.