I began experiencing this problem with not being able to download songs (with a Zune Pass). Did the recommended procedure. Now, not only can't I download songs, but all the content I've already downloaded won't work (gives me the same error). The cure is worse than the disease??? Here's the error message (which, when you DO click "Web Help", returns this message: "Unfortunately, there is no specific Web Help message for this error yet." That's real helpful.):
"Can't verify your media usage rights. A local firewall might be blocking access to the Zune service. Check your firewall settings and restart the Zune software. If the problem persists, click Web Help. Error Code: C00D12F6"
EDIT: When I right-click on a song in the Zune software and select "Properties", DRM shows "Yes - invalid license (has no usage rights)". I think NOT!