Every family's got one?

AncestryDOTcom emails me intermittently to inform me that so-and-so, also in their DNA database, is my Nth cousin. If it's a close enough connection, I'll tell my mother the name and she can usually work out whose son or daughter they must be. With the latest person - a "1st or 2nd cousin" - she wasn't able to do so. I Googled the mystery man's name. He appears to be a professional astrologer.