Does your factory have enough power? If the power isn't enough, everything that needs energy goes slower. So an inserter might take too long to move, and the item moved out of range before it can be grabbed.
It looks like it took the wrong ore once, the furnace is now filled with metal which can't be used by the assembler nearby. Make sure the inserter only gets the right ore, or place the metals from the furnace in a chest, and from there into the assembler. And yes, lack of energy could be the problem.
Then probably problem is energy, because energy bar on factores ar under 50%a aprox. Its 4 misión of tutorial, first with electricity and I didn't created any steam machine rather than default in mission