[PROBLEM] volume via rest api doesnt work with multiroom

[LeGuiz]

I know the usage scenario can be disturbing, but the receiver is near my amplifier and I want to be able to have basic control from the keyboard accessible near the amplifier. there is no interface whatsover on the receiver rpi just dac hat and rca to amp.

I have try to activate the "USB volume knob" option on sender but got not more luck, still I can see the volume change when I "curl" but it doesnt quite reflect on the receiver as it shall be...