Unexpectedly, the external display went black and became unresponsive. This occurred after I decreased the brightness level and a few hours passed.
Expectedly, the external screen initially turned off. However, after the Cosmo was off for a few hours, I pushed the left toggle button and the external display was still dimmed but expectedly showed the 8 circular app icons. I could not get the external display to return to show the time, date, etc.
I then opened the Cosmo and Android was working fine. I then closed Android and the external screen was black and the two LEDs in the toggle switch on the front cover were a solid red (not blinking). Pushing the toggle switch buttons or the silver colored button on top of the Cosmo did nothing.
After rebooting the Cosmo, the front cover external display worked as expected.
