HDMI NOT WORKING ITS 3 meters long

[Martin onlyme]

I have just fitted my tv to a wall and cables are concealed behind plaster. These cables are about 4 mts long. My sky box works fine. But my LG blue ray player and my Apple TV do not work could any offer me any help?

 

[makkem]

Hi
So are you saying that there are 3 HDMI cables behind plaster and only one of them are working ?
Have you tried plugging the Sky HDMI into the LG and see if it works and vice versa ?