I did, only HDMI is plugged in!Did you check markus_g's question about the VGA connection?
Fully agree. I could solve the issue with "Gefen HDMI Detective Plus", unfortunately very expensive (> 150 EUR ).This doesn't surprise me. After all, we already saw that the audio renderer seems to be unavailable. That was what caused me to suggest disabling skin sound effects. You do have [what looks to me like] quite an unusual sequence of audio-renderer-connected/disconnected messages in the standby/resume cycle. My guess is that the underlying cause of the issues is HDMI handshake/compatibility issues.