Using Arc to a Denon sound bar doesn't start automatically

I have Sky Q box connected to the projector on HDMI 1 and from there via ARC via HDMI 2 to a Denon S217 sound bar.

Every time I start the equipment up, the screen image blinks on and the blanks multiple times without stabilising eventually it reverts to a screen full of digital noise.

If I manually go into settings and select HDMI 2 then select to HDMI 1, the screen image locks in successfully.

Obviously, the system works but startup is not working. How do I make it all lock in first time?

Hi, please try to connect your Sky Q box to HDMI IN of the Denon S217 sound bar and after that from the sound bar HDMI OUT to screeneo u4 HDMI 2 (ARC). That’s working for me with my amazon fire tv cube.