Jehovah's Witnesses do not believe Christ was the Son of God. They believe that he was just a (sometimes minor) prophet.
This disrupts the "trinity" -- "Whoever is without the Son is without the Father" ring a bell? By making a derision between the Holy Spirit, God, and the Son, this causes reality to be 2-dimensional or duality-based between Father and Holy Spirit. (think of base and height without hypotenuse)

Jehovah's Witnesses are a door-to-door scam, directly from Satan.