LG 84WT70PS Owner's Manual page 59

Display Sharing function does not operate.
Problem
Display Sharing connection is
not working.
Display Sharing function does
not operate.
The monitor is not detected in
the Device list of the PC.
Display Sharing is
disconnected.
y If Display Sharing connection is not working, try to connect again after
you remove a monitor's name in a device list or reboot a sink device.
y If Display Sharing connection is not working, try to connect again after
you go in 'Display Sharing' menu and then turn 'Off' and 'On' at a
monitor.
y If Display Sharing connection is not working, try to turn 'Off' and 'On'
the monitor.
y To reconnect Display Sharing, remove the Monitor from your PC. Then
search for and add the Monitor again.
y Supported OS is Windows 8.1. And a sink device has to support
'Miracast'.
y If the monitor is not displayed in the device list of your PC
intermittently, turn Display Sharing off and on again, or restart your
PC.
y If Display Sharing is disconnected when a sink device (ex. Notebook)
fall in the screen saver, check a sink device's network setting or turn
off the screen saver function.
TROUBLESHOOTING
Resolution
59