Apple TV4K not working through receiver

I have been trying to connect Apple TV to receiver and out to a projector. To accomplish this, I have connected via HDMI cable Apple TV 4K to a Sony STR-HD750 receiver. Then via HDMI on the receiver, I have connected my older Optoma Projector (that has only 1 HDMI input and no audio outputs). In this configuration, the projector receives NO signal at all from Apple TV. However, if I plug Apple TV directly into the projector (via HDMI) it works fine, but I have no way of getting the audio into the receiver and out to the 7.1 speakers set up. I have tried the same passthrough (Apple TV to receiver and out to projector) with another brand of receiver and with different HDMI cables and had the same problem. Is it possible that receivers do 'something' to the HDMI signal before redistributing it out via HDMI out ? I have also tried the same set up with a Roku and had the same problem. Everything works fine only if plugged directly into the projector, but not connecting it via a receiver. Anyone had this problem and a solution for it ?