I have very few PNG photo rejects from Adobe, from which I cannot determine why, and then re-submit where it is accepted. This one, however, has me stumped. The focus, detail, and overall quality appear to be OK...what am I missing?

I revisited this file, as advised from both of you, and it was accepted.  This is the first time, of which I am aware, in which I was rejected due to tone or tinge.  Thanks!!

Check your original in the Histogram panel. I’m seeing plenty of midtones, but not enough highlights & shadows. 

The cutout looks good, but it seems the overall image has a rather greenish tinge…