1. Please check and make sure the correct input source is selected.
2. Do not mix up HDMI 2.0 and HDMI 1.4 input ports as it may lead to a blank screen.
3. If a Windows-based notebook is connected, press "Windows Key + P" and make sure the Project settings is either on Duplicate or Extend.
4. A defective HDMI or VGA cable can also cause such no signal problem.