I'm having the same issue. Up until just a few or more days ago MM worked just fine; And then it stopped working altogether.
I've configured the usual, Rebooted, and still no luck.
I updated my Win 8 machine to the free Win 8.1 months ago and MM worked fine.
I just can't get it to do what it's always done.
It's been updated as well to its latest version.
I'm thinking of downloading it again from fresh to see if that works..... I'll let you all know.