I'd do what others have suggested and first swap out the cables. It could also be from a faulty tv input (HDMI?). So try switching to another available input.
Did you also try unplugging the tv, not just power off/on which just puts it on standby. This should reboot the internal operating system, similar to smartphones. Has fixed many problems with my Vizio smart tv, including occasionally losing audio for no reason. Or not syncing with the correct picture format. Want's to display in
Ultra Panavision now and then? :S
Also, had one dead HDMI input. Not a fan of Vizio.