Too bad, I had such big plans for this 🙂
So, now that I’m at a dead end, let’s go over the different ways to figure out why a node is red…
Point to the node and wait for the tooltip to show the first error:
Right-click the node and click Show Messages.
(Log port type details can be useful sometimes, but not in this particular case.)
Read the documentation.
eX-SI 
The vertex positions that make up that poly(s)?
That’s right, I have to move those.