Question

Just as the question says:

Why can't I hear any audio out of my Control Room (CR) Audio Output on a StudioLive AR Mixer?

Answer 1

When PFL or AFL is engaged anywhere, the Control Room and Phones switch to the Solo bus, so you'd only hear what's there. If you PFL/AFL'd something with no signal, or if the Solo volume is down, you won't hear anything.

If an AR mixer is reported as no audio from Control Room or Phones, it likely has no audio from either, because there's a PFL or AFL button depressed without realizing it.