New TV No Cable Signal

I just had to buy a new TV. I bought a Samsung 50" Q8F. I connected everything and the TV claims the cable box is not on when it is on. I can connect the xfinity streaming app just fine, but that takes a while to boot up. I have powered off the cable box and TV a few times each, but nothing seems to be working. My other HDMI devices connect just fine. I have even moved the HDMI devices around to see if it was a bad port.