Update: I replaced my larger monitor with a standard monitor and the 8940 worked fine through the KVM.  I spoke with IOGEAR and they indicated that the KVM was old enough that it may have compatibility issues. To test that theory, I bought a cheap KVM to start: [URL] Lo and behold, it worked and I can now use the 8940 with the 3818 monitor through the KVM. The only problem I have now (and will open another post) is that I can no longer get the Dell Display Manager to recognize the monitor and thus am unable to use the DDM on 4 machines where I was able to do so previously.   One MAJOR step forward, and a small one back....hopefully. Thanks to all that helped with your excellent troubleshooting ideas that helped to get closer to the solution!  Much appreciated. 
I have a Dell Latitude Inspiron 3670 that I bought in 2019 and use through a KVM switch to my Dell 38" monitor. The KVM is an older IOGEAR 4 port GSC1794 device from 2013. I just purchase a Dell XPS 8940 that will connect directly to the monitor and works fine. However, when I try to connect through the same KVM as the Inspiron, the signal is never acquired and the monitor says it cannot find the HDMI 1 signal. If I instead plug the HDMI into the slot on the graphics card instead of at the top of the XPS, when I power cycle the computer, the Dell logo does come on the screen, but then when it switches to go into Windows, the screen goes black and the same message about not finding the HDMI 1 signal appears again. Any insights on how to proceed? It's very odd that a computer from 2 years ago works fine but the new one does not. Thanks in advance for any insights. Thank you,  Scott
XPS 8940, IOGEAR KVM, monitor not working