He prob has the scanner audio disconnected from the server or its been muted by mistake. I have this happen to my feed from time to time. Also if the power went out the scanner may have to be physically turned on and he is unaware. Try using the contact feed provider and send a quick nudge to him/her
The feed description says it is digital audio. Plus that news article saying that analog communications had ceased was from back in May. I doubt the feed has been running silent all that time.
As mentioned before, best thing to do is send a problem report to the feed provider. Make sure you accept incoming PMs so the feed provider can communicate back with you.