[ubuntu] Redshift Stopped Working

Ubuntu 16.04:

Redshift is a program that changes the gamma levels/screen temperature of your screen when it gets late. It's been working for me for the past month and it stopped working today seemingly out of the blue. The Redshift site says the following:

I am not getting any error messages when I manually attempted to change the gamma ramps with Redshift, it's just not executing my commands. This leads me to believe it's most likely a graphical issue, something with the video drivers. I am on a laptop with onboard video. The driver that I have in 'additional drivers' is currently listed as:

'Using processor microcode for Intel CPU's from intel-microcode (proprietary)'

I've uninstalled redshift and reinstalled but still no luck. My only guess is that the graphics drivers got changed on my system. How can I revert back to the default graphics settings when installing Ubuntu?

Thanks,