Could not enable HDR on my new Apple TV 4K and my Sony XBR65X900E

I just received my new Apple TV 4K (released September 2017), and I updated its Firmware and TV OS to the latest version.

I connected it to my recently purchased Sony XBR65X900E, which is a 4K TV with HDR. About the TV:

https://www.sony.com/electronics/televisions/xbr-x900e-series

Sony eSupport - XBR-49X900E - Support

As soon as I installed the TV, I upgraded it to the latest Android OS.

I also used I used an HDMI 2.0 4K UHD, with HDCP 2.2, 26AWG, that supports HDR, 3D, etc, by MIC Cable, as follows:

https://www.amazon.com/HDMI-Cable-Feet-Supports-Connectors/dp/B071HB7S7F

The Sony TV recognizes the Apple TV 4K, which is connected to the Sony TV HDMI Port 1. The Manual does not detail which HDMI Ports are HDR, I have to assume they all are HDR, as there is no mention of some HDMI Ports not being HDR.

In the Sony TV Settings, there are five HDR Settings options (ON, OFF, AUTO, HDR10, and HDR Dolby), and I select HDR10. Immediately I see the screen of the Sony TV displaying the Apple TV 4K inputs way too bright, the image becomes white washed, but I can see the icons of the Apple TV 4K Menu, they look awkward, but they are visible.

Then I proceed to go to the Apple TV, Settings and I try to enable the HDR. The Screen goes dark for about 1 minute or two, and then it displays the following message: "We switched your TV to its previous format. You may need to choose "Ultra" or "Deep" color settings on your TV, or try a different HDMI Input. Check your TV's User Guide for details.".

This means that the Apple TV 4K did not recognize the Sony XBR65X900E as an HDR capable TV.

I then tries the same settings on the other HDMI Inputs 2, 3 and 4, to no avail. The Apple TV 4K "HDR" is not recognized on any of the HDMI Inputs.

With so many moving parts, I am at a loss, and I am making this posting on the Apple Community to try to find an answer. Any replies will be most appreciated,

Sincerely,

Victor.