If the settings are too far off for refresh rate, resolution monitors can do that. Check your settings.
Bob
I have been connecting my laptop to an external monitor via hdmi but after about 5 minutes, the monitor goes to sleep. I tried again with another monitor, and the same thing happened. I have tried different projection settings (duplicate, extend, 2nd display only, etc.) yet every time I plug in laptop to the monitor, it will only project for a short time before the monitor goes to sleep. With the monitor plugged into an old computer box, this does not happen so I am fairly certain the issue is from my laptop and not the monitor.

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