The Meaning of Life, the Universe, and Everything.
I have been building an auto smelter and I've come up with a problem.
As you can see in the picture, I put a a hopper facing the furnace but whenever whatever I want to smelt goes into it, it doesn't transmit to the furnace and stays in the hopper. This is not true for fuel items. There is no redstone source near it and it is correctly facing the furnace.