Can’t equip sacred flame in weapon slot two but slots in weapon set one

Hello trying to equip my sacred flame to my weapon slot two but it will not let me but it will let me set it in weapon slot one off hand and main hand even let’s me set it two second weapon set main hand but not off hand I have all my gems off character and all attributes are satisfied also have gem restrictions off please help thank yo

Kinda late, but first equip weapon and then Scepter. Otherwise it defaults to left side