AppleTV 4k and Epson 3800 Do Not Play Well Together

I bought a new Epson 3800 (very happy with it) and I can get it to work well with a Denon X4300H using multiple HDMI ins to the AVR (Tivo works, Xbox works), but when the source is AppleTV, it displays HDMI1/2 - No Signal (whichever I use on the Epson).

I did the following troubleshooting to help narrow it down, but nothing seems to work

• replaced HDMI cable (it is long - 30 feet, but every other source works passing through it). No diff.
• Played with Denon 4k settings and Monitor1/2/auto settings. No avail.
• Played with AppleTV 4k settings. No avail.
• Played with Epson 4k settings. No avail.
• I can get AppleTV to work with multiple TVs through Monitor 1/2/auto and through Zone2
• But the exact same approaches using Epson as target fails
• I tried bypassing the Denon and connecting HDMI directly from AppleTV to Epson. No avail.

Honestly, I’ve enjoyed playing with different setups and settings, but it would be nice to get it to work. In short, I’ve replaced multiple hdmi cables (the issue doesn’t follow the cables), I get it to work with multiple sources whether bypassing the denon or not, I get it to work with multiple destinations. The only combination that doesn’t work is if AppleTV is the source and Epson is the destinations (whether or not I have the Denon in the middle).

Any ideas? I’m open to additional tests/tweaks. I suppose I could try a diff AppleTV unit, but that’s about all I haven’t tried (I only have one Epson :)