1. Check the HDMI port on the back of your Smart TV and make sure it is securely connected to the HDMI port on your home theater system.
2. Make sure all HDMI cables are firmly connected.
3. Restart your Smart TV and your home theater system and try again.
4. If your HDMI ports are labeled, check that your Smart TV is connected to the Output port on your home theater system.
5. Try switching to a different HDMI port.
6. Make sure your home theater system is updated with the latest software.
7. Check your Smart TV’s settings to see if HDMI-CEC is enabled.
8. Check with the manufacturer of your Smart TV and home theater system for additional support.