I figured out the problem.
Even when using a honeycomb bed, the Z axis probe could not bottom out on my 3mm plywood test piece.
I stacked up several pieces of the plywood and that solved the problem. I guess I will need to fabricate some thicker feet for the honeycomb bed.
I was able to run a material test pattern.
I used the recommended 6000 mm/min 50% power setting for the text, but it was too light to read easily.