Cannot choose Dolby Vision

Hi there, i Hope this is the correct place for this thread.

I cannot choose Dolby Vision in Apple TV settings.

I have the following setup:

Apple TV 4K is connected to a Denon 3500h AVR.
The Receiver is connected to a LG CX 77 TV.

I can only choose HDR in the Apple TV settings.

In the TV Apps of web os Dolby Vision is supported.

In the TV and the Receiver the advanced HDMI is activated.

Has someone an idea why i cannot choose Dolby Vision in Apple TV settings.
Afaik all my Devices support Dolby Vision.

Thanks in Advance

It’s your HDMI cable.

Run through the Apple users guide here