Redshift/F.lux not working on Ubuntu 16.04
In a console type
redshift -l list
then I typed
redshift -l geoclue2
then it just worked. I can even close and reopen it now and it works fine.
I tried to get both f.lux and Redshift to work without any solution so I just opted to go another route. So I went to the Ubuntu Software Manager and installed Night Light slider as pictured below. It works and certainly isn't making me die from strained eyes and a headache from earlier in the evening due to no sleep.
Search for Night Light on Ubuntu Software:
Once installed, it just appears in your top right drop down menu and can be toggled to user preference.
So I figured out how to use Redshift with my system. Basically, I was using the wrong display driver. When I went to the Additional Drivers tab in the Software & Updates app, I noticed I was using default Nouveau driver instead of the latest NVIDIA driver, and had the other tab set to "Do not use the device".
when I switched it to the NVIDIA driver tab and HDMA Driver with DKMS Format (daily-dkms) tab, and restarted the machine, it finally worked.