After doing a tcpdump on the Zenoss server using "tcpdump -s 65535 -w
filename.dmp"and loading the results into wireshark I found this in the traffic between Zenoss and the Domain Controller:
Turns out the Zenoss server was looking for an SPN of the FQDN of my Windows host and not the hostname. We went ahead and added a new SPN for the FQDN using "setspn -S HTTP/
< FQDN > < hostname >" and that resolved the issues!