Why is my Smart TV not displaying any image or sound from external devices?

1. Step 1: Check the external input connection.
2. Step 2: Confirm that the external device is turned on and is properly set up to access the TV.
3. Step 3: Select the external device in the TV settings.
4. Step 4: Try restarting your TV.
5. Step 5: Check the instruction manual of the devices.
6. Step 6: Unplug the TV from the wall outlet and wait for 30 seconds and plug it back in.