C78 Hub not recognized by 2017 iMac

The C78 hub I just received generates an error message when I connect it to my 2017 21.5 inch Imac. When I check in the System Report under About This Mac it shows “no device connected”. This iMac has

“Two Thunderbolt 3 (USB-C) ports with support for:
DisplayPort
Thunderbolt (up to 40 Gbps)
USB 3.1 Gen 2 (up to 10 Gbps)
Thunderbolt 2, HDMI, DVI, and VGA supported using adapters (sold separately)”

What is required to solve this?

Hi @Miket,

Thanks for joining the community. Is your Mac system the newest version? You can try to upgrade it, see if that helps with your problem.