I figured out the issue. First of all, if I am opening the Epic Launcher for the first time after a reboot, the marketplace is visible and functions correctly. The error does happen until I hit “Yes” to download the required plugin from the Marketplace. Which, in my case, is the Substance Plugin.
Second thing is that even though I was closing the launcher, I did not realize that the Launcher stayed open in the system tray. So even though I close the launcher and open it back up, I would get the same error.
After I closed the Launcher from the system tray, I searched for the plugin directly from the Marketplace and was able to download it without issue.
Matt