Why is my external monitor not working?
If you have a 4k or 5k monitor attached to your Mac and notice Luna Display isn't running properly, try removing the monitor to see if there is any difference.
The Luna Display dongle cannot be plugged into the Mac on the same side as a 4k or 5k display, and we suggest plugging Luna into a port on the opposite side of the display.
If a 13" MacBook Pro (with USB-C ports) is in use:
Plug-in Luna Display to the MacBook Pro first, with both apps running, and then plug-in the 4k or 5k monitor afterward.
If you have a newer M1 Mac with Apple Silicon, there are some limitations on the number of external displays allowed. For example, the M1 Mac mini supports only one display using Thunderbolt/USB-C. Be sure to check Apple's device technical specifications to see what is compatible with your machine.