Subwoofer suddenly not working properly with receiver?

I could really use some advice from home audio guru's here! So suddenly, my DCM subwoofer isn't picking up a signal from my Onkyo receiver. There was no specific event that caused this, and it just seemed to happen out of nowhere. From all testing, the receiver appears to be performing 100% properly and all other speakers are getting their signal...

Normally, the sub will be in passive mode (red light), until it picks up a signal from the receiver and then it will go active (green light). This no longer happens, and it stays in passive 100% of the time. What could be causing this? I checked all cables, tested everything else I knew how to test and all appears to be well. I even checked to ensure the woofer was enabled in the speaker settings, in case they reset. It's still enabled. I'm out of ideas here...

 

I little more information please, would help a lot? How old is it? Is it auto signal sensing? if so, can you bypass it? How is it connected to the receiver, single LFE cable? What model powered subwoofer do you have, so we can look it up, and see exactly what features it has.

 

^ Thanks for the reply, but I was able to get it working. It's coax direct cable connected to my receiver, and the sub just totally went to sleep on me somehow. I actually unplugged the sub, and plugged it back in and wallah! It now detects the low frequncy signals from the receiver as it has every time for years. That shouldn't have happened though, and I am suspicious as to the cause. Something may be going downhill, but I can't really complain, as I've had both the sub and receiver for over 12 years.

This is the sub, just for reference https://www.amazon.com/DCM-Subwoofer-SW10-Discontinued-Manufacturer/product-reviews/B00005T3K6