Issues using ZPA to print to Windows Print Servers/Spoolers

Anyone else have any luck getting ZPA to work with a windows print server? We have all our printers shared off a server (not direct printing) and opened up the relevant Windows printing ports and still some of our users come up showing printers offline, or they submit a job and it comes through with 0 pages to print. I just cant seem to narrow down the problem. Even when i opened all ports to the print-server to see if i was missing any the same errors happen, and strangely they come and go. Sometimes it works fine… sometimes not.

This is in multiple sites to multiple print servers.

Matt, is there any kind of authentication requirement for the print servers? Given the description, I wonder if the user’s device needs to be authenticated (via Kerberos??) prior to accessing these print servers.