iMac as secondary display not work
So I have a 2019 13-inch MacBook Pro and 2019, 27-inch 5k iMac. I am attempting to use the iMac as a secondary display for my MacBook with an Apple Thunderbolt 3 (USB-C) cable, but I can't get it working. I've tried activating Target Display Mode via Command-F2, but nothing happens. Any help would be appreciated!
iMac Line (2012 and Later)