Here's what I got from Jasonl at Silicondust.
I presume that this is only affecting CIII/Global HD? They changed the configuration of their broadcast recently and this resulting in a mismatch in the stream ID they are broadcasting. WMC can't handle this mismatch, and it results in a no signal or service unavailable error. We are attempting to reach someone in engineering at the station in order to notify them of the issue so that they can reset their configuration, which will allow WMC to work again.
I guess we will have to wait until Global fixes it.