I replaced all my IInventory by IItemhandler
But the error look like the same as before a null slot: https://pastebin.com/bdgUteFt
But in my TileEntityClass, my inventory stack look like this :
private NonNullList<ItemStack> machineItemStacks = NonNullList.withSize(4, ItemStack.EMPTY);
And i have only 4 slots :
this.addSlotToContainer(new SlotItemHandler(tileentity, 0, 14, 8));
this.addSlotToContainer(new SlotItemHandler(tileentity, 1, 51, 8));
this.addSlotToContainer(new SlotEnergyFuel(tileentity, 2, 14, 56));
this.addSlotToContainer(new SlotMachineOutput(player.player, tileentity, 3, 114, 7));
So all slots are fill with ItemStack.Empty and are not null no ?