You may be having a "handshake" issue. Try changing the order you boot the computer and select HDMI 1 on the TV.
Try a different HDMI cable. Try a different HDMI input on the TV.
The video resolution of the computer could be too high for the TV so it won't show anything or it may indicate no signal.
If you have another monitor connected to the computer set the TV as a 2nd display or extended desktop. Then you can change the resolution to match the native resolution of the TV.