Can you try the other HDMI cable just to rule that out as a possibility? I assume your TV isn't 4k, but that shouldn't matter. The Express 4k+ should work just fine on pretty much any HDTV. If the Roku 3 was damaged by a lightning strike it's also possible that the HDMI input on the TV was damaged, so try another one or another TV or try another HDMI device like a Blu-ray player to verify that the HDMI input is ok.
And as always, if you're using the TV's USB port to power the Express try using the supplied power adapter.
One other possibility, albeit slim, is that the Express was returned after someone set it up on a 4k TV. You can try a factory reset by locating the reset pinhole and using something like a paperclip to press and hold the reset button for no less than 30 seconds with the power connected to the Express.
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