Bypass any video switching or signal-splitting devices connected to an HDMI output.
Do not use a digital video switching device or HDMI-splitter as such devices may remove the necessary HDMI "handshake" that needs to occur between the source and destination devices. If the best video input connection on the TV is a DVI connector, try using an HDMI-to-DVI cable. An HDMI-to-DVI adapter may work but will not be as reliable as a straight HDMI cable or an HDMI-to-DVI cable.
Which device is being used?
Other connected video device