Converting list to string and return

I’m playing with elixir and graphql and I want to return my model for a given argument, in this case, it will be ean_code so

def get_product(%{ean_code: ean_code}) do
  item =
   Item
   |> where([t], t.ean_code == ^ean_code)
   |> Repo.all()

   {:ok, item}
end

get_product should return all if ean_code` match the given value, this is my mutation

field :item, type: :string do
  arg :ean_code, non_null(:string)

  resolve fn _, args, _ ->
    Product.get_product(args)
  end
end

and error is

To be converted to a string, a list must either be empty or only
contain the following elements:

  * strings
  * integers representing Unicode code points
  * a list containing one of these three elements

Please check the given list or call inspect/1 to get the list representation, got:

    [%Scan.Product.Schema.Item{__meta__: #Ecto.Schema.Metadata<:loaded, "items">, br

The error is self-explanatory but I’m a bit confused on how to solve it, so can someone help me understand how can I convert this, thanks.