Hello dora.
I will try to explain it to you in the simplest and clearest way possible.
The AutoLoot is for taking objects from the ground and these will remain in the backpack.
On the other hand, we have the ItemStorage, which stores the backpack items in the inventory or depomail.
If, for example, the backpack is already full of pots, you will not be able to take any other items.
Instead, there is an option that allows you to always leave a slot so the pots/food will not use that slot.
This option is called "Reserve slot for autoloot" (it appears in the attached image). All you have to do is activate that option, select the space that will remain free of pots / food (so that they are not sent from the inventory to the backpack).
In this way you can continue taking items from the ground and send them to the inventory or depomail.