iMac 2017 5k host, iMac 2017 21 target display mode I am using my iMac 2017 5k as my main machine and want to use my 21 inch 2017 iMac in target display mode.

When I try Command + F2 I hear a beep and nothing happens. I have also tried doing it at the login screen and also tried fn + Command + F2 but nothing worked. What am I doing wrong? Is this possible?
Neither of your Macs support target display mode. Below are the Macs that do.


iMac (27-inch, Late 2009)  
iMac (27-inch, Mid 2010)  
iMac (Mid 2011-Mid 2014)  


For more information see Use your iMac as a display with Target Display Mode.