Check the instruction booklet of the TV to make sure that the TV is HDR compatible.
Ensure that all the cables connected to the TV are plugged in correctly and securely.
Check the TV settings menu to see if HDR is turned on and functioning properly.
Check the content that you are streaming to make sure it is HDR compatible.

1. Check the instruction booklet of the TV.
2. Ensure all cables are plugged in securely.
3. Check the TV settings menu.
4. Check the content being streamed.