Harris has a growing problem of not being nor representing real black Americans, or as the critics call themselves, A.D.O.S. (American Descendants of Slaves). This group of black voters see her as another Obama--someone not fully connected to the experience/lineage of slaves and all they and descendants suffered and built to make this nation--but go out of their way for every other group--a common criticism of Obama.
From professors to the most grass roots of individuals, their presence is growing (just look up Kamala Harris / ADOS on YouTube), so much so that the world's most honest news outlet--MSNBC--attempted to delegitimize her critics as Bots (here we go again). This movement is also the main supporters of reparations for A.D.O.S., and despite Harris claiming she's in favor of that, her support is seen as an attempt to con black voters into backing her, since she has no chance without this voting block.