macOS not recognizing external display

Issue

External display not detecting signal from a Mac laptop.

Environment

Post-2017 Mac laptop

Description

I have a docking system, and I seem to have done something that makes my second monitor not receive signals from my computer. I probably adjusted a setting last fall and forgot what I did.

Resolution

1. Connect the USB-C display adapter/dock to a different USB-C port on the laptop (if available), ideally the rear left port. The rear left USB-C port is typically better suited for conveying display signals and Ethernet connections.
2. If no other ports are available or no ports work for connecting to the display, make sure all cables are firmly plugged in and that the monitor is on.
3. If you are still having trouble, please contact your department or unit IT support for assistance and possible hardware repair.