XPS 15 9570 - WD19TBS USB ports not recognized

Just bought a thunderbolt dock mainly to connect monitors, which works fine. However, I cannot get the computer to recognize the dock or its USB ports. For instance, I can't install Firmware update because it says there is no dock connected. Likewise if I plug a USB device into the dock it won't work. 

Steps I've tried:

1. downloaded current Thunderbolt chipset driver (driver shows up in device manager)

2. Tried the steps in this post: https://www.dell.com/community/XPS/XPS-15-9570-problems-with-Thunderbolt-Dock-WD19TB/td-p/7576930

3. Updated Citrix software

Any ideas on how to get this dock to work properly?