HDMI Stop working after Macbook OS Update HDMI Stop working after Macbook OS Update to Mojave Version 10.14.3.  Was working perfectly. I tested cable and monitor and it works on other laptops.
So after some Google searches I found one fix that worked. Update the Display Link Driver located here:  https://www.displaylink.com/downloads/ 

Not sure what happened during the new Mojave Update to version 10.14.3 but after installing this new driver, my HDMI port to second monitor is now working.