Always, and I do mean ALWAYS, suspect cables first. Can't remember how many wires are in an HDMI cable. I think it's 17, each one with a flimsy connection to a terminator that rarely holds it secure. Most TVs make the situation worse by requiring the HDMI to be plugged in horizontally, putting even more pressure on the weakest point.
I've had cables fail that look to be in perfect condition; 30 pin, HDMI, Lightning, USB, you name it and there's probably an instance of a failure somewhere.
I recently sold an amplifier to a guy. 24 hours later, he was on the phone telling me it didn't work properly. I offered him his money back and picked it up. He took $50 less than he'd paid me for my inconvenience. Took it home, plugged it back into my system and its been working perfectly ever since. That guy spends more money on cables than most people spend on an entire system but couldn't get past the fact that one of his interconnects had failed.