If Laptop External Monitor is not working, detected, or displaying anything when connected, or Windows won't recognize second HDMI monitor, see this post.

A dual-monitor set-up can help to increase productivity, but what if your second screen isn't being detected? Here's what to try to fix the problem.

If the Windows 11 calendar is not opening on second monitor, check your display settings and the taskbar settings first, or use a third-party software.