Parental Controls are still not blocking

Parental controls are set up through the admin tools (the 10.0.0.0.1). BUT the Parental Controls are still not blocking YOUTUBE and other sites I don’t want my kids on when they are to be doing homework. I can not get this Parental Controls that Xfinity has to work.  I have the Parental Controls set up correctly as I have watched and read so many articles on how to do this…. They still are not blocking out the times I want my kids to be doing something else.  HELP…!!!!!!!