MOST-H.U.R. MB-S (OPTI-1) No Sound

I've installed the MOST-H.U.R. MB-S (OPTI-1) with a Pioneer AVIC 8200NEX (2005 SL500) without steering wheel controls and I am not installing the AM/FM antenna. I only want this system for the android apps and navigation. After the install I am not getting any sound. This is pretty easy on the wiring:

MOST-H.U.R. MB-S (OPTI-1):
Blue => Blue/white from radio
Red => 12v continuous from Fuse block
Black/red => ground (brown)
Fiber cable connected fine
RCA connected to the L/R out on radio

Pioneer AVIC 8200NEX:
Yellow => 12v Continuous from Fuse block
Black => ground (brown) Cig ligher
Orange => gray/blue (variable voltage) Cig lighter
Red => ACC 12v Cig lighter
Blue/white => blue on MOST-H.U.R. MB-S (OPTI-1)

I do see a light coming from the Optic cable on the Mercedes side, so I'm assuming the amp is powered up.