I figured it out. The problem wasn't the CCwGTV and AVR. It was actually the projector which is a 2019 model (Epson 3800). When I output the AVR signal to an older computer monitor the CCwGTV worked fine through the AVR. Because the projector is so new it was sending an extended message during the HDMI handshake which the AVR couldn't handle. I went into the projector settings and found EDID which was set to "Extended". When I switched it to "Normal" the CCwGTV worked fine.Just received the new GTV Chromecast and I have a similar issue. It works fine when plugged directly into a TV and projector but when I plug into an AVR that's connected to the projector I get no display. I have a Gen 2 Chromecast and that works just fine with the AVR. I am guessing this is some kind of HDMI handshake issue since I have an 8-year old Denon 2113CI AVR? This Google support post would seem to suggest this kind of configuration is not supported:
But I imagine this is a relatively common setup and that thread doesn't seem to have enough posts to think this issue is pervasive. I would be OK upgrading my AVR if I was certain that would fix the issue but in the support post there are people with more modern AVRs that are having the issue. Anyone have thoughts on a solution?
A couple notes, I have a Windows PC also hooked up and that was working fine in 4K. After getting the CCwGTV to work, when I switched back to the PC input, the resolution somehow got scaled back to 1080p. When I manually put the PC display settings back on 4k and switched back to the CCwGTV input, it stopped working again. Turning the AVR off and on again fixed this problem. Also, though the CCwGTV automatically negotiates a 1080p connection, I can actually go into the CC settings and set the resolution to 4K 30Hz and that works fine through the AVR.