LG TV Says No Signal When HDMI Cords Are Clearly Plugged In The Right Way?

I too am having this issue. When I first plugged my box into our LG tv it worked just fine. I am using a monster HDMI cord, we switch from plugging the computer and the Xbox. They had been working fine for a few months. Now when I plug in the box, it says
invalid format, which is coming from the tv its self, NOT the box. After plugging the cord into the computer, it works fine. Switch right back to the box, nothing. Iv tried wiggling the cord, nothing, changing the tv input, nothing.

No signal on the tv can mean a couple different things.

1. You want to make sure that you are on the right input on the tv.

2. You want to make sure that the HDMI cord is plugged in snugly in the back of the TV and Xbox.

3. There is Two different HDMI ports in the back of the xbox you want to make sure you have it plugged in the one that says out to TV.

My TV does the same. Starts the disc and plays all the 2d content, then when the 3d signal kicks in the TV loses the signal. If however I unplug the HDMI cable and plug it back in again, the 3d image is displayed on the TV.

My TV is the LG OLED55E6T TV (firmware version 05.30.15

LG's HDMI support is notoriously unstable, not sure if it is the way they handshake or whether their software is poor but it is a long standing complaint you can find in many places on the internet.

Xbox 360 had issues with LG TV's as well (do a web search for xbox one lg tv hdmi and you'll get pages of results including PlayStation issues connecting to LG TV's so not limited to Microsoft).

Things to try:

On your TV that it works with, set your Xbox One to a lower resolution i.e. 720p then plug it in to the LG TV and see if it works.

Check for a TV firmware update

Reset TV to factory default settings

Try other HDMI cables

Try a HDMI to AV converter for your sister's TV and use AV cables with your Xbox One when using that TV.

Hi,

I have the similar problem. My TV is a TCL branded. Sometimes when I connected my Xbox One with HDMI to my TV, it is all black out. I kept unplugging and plugging back like many times, still like that. I shook the HDMI cord lightly instead, then sometimes
there came signal. I don't know if it's my TV issue or else. Should I buy a new HDMI? I suggest that you try to shake the HDMI cord lightly, it sometimes might finally give out the signal. I hope my suggestion help!