I'm having great trouble trying to make the HDMI port work with our LG TV. The laptop displays perfectly with our monitors but refuses to with our TV's. A few users here have been having this issue. Has anyone else had this issue and can you shed some light onto why this is happening? Or a possible fix?
Have a look at the following link which seems to be the same problem you are experiencing.
If this is a newer LG OLED TV that supports 4K HDR, you should have an option somewhere in your TV's settings to manage the "HDMI Deep Color" setting or something along those lines. Try turning that on or off for the HDMI input you're trying to use with the laptop. You'll probably need it to be off.