The TV says "No Signal". This is a new TV. - DirecTV

The TV is new. I set up the other 2 new ones with no problem. The Direct TV box is on (blue light) and the network light is green. The message on the TV screen states "no signal".The Direct TV remote turns on/off it's box, but has no effect on the TV. The TV remote brings up message "HDM12/MHL" when I press its "info" button. It has been like this since May, when I bought the TVs. How do I get the picture to the TV from the Direct TV box with the Direct TV remote?

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