Why is Bernie silent and not campaigning for Canova?

I'm to the left of Jill Stein, but I was a very aggressive Sanders supporter since January, and I've been following his career for almost a decade now. When he supported Clinton I was upset, but I trusted that he sincerely believed it was the most prudent choice (although I disagree). But this silence on Canova (and please don't say he's resting as an excuse, since he found time to help Clinton!) is too distressing. What the hell is going on!? I can't think of any legitimate reason for this behavior? -Solidarity