Self made item despawning when drop

so today i made my firsts items and one of them disapear when it drop on the floor,
hear is the json entry,i Don’t know why it happen can someone help ?
also started Learning yesterday about modding cdda
“id”: “ninja_shoes”,
“type”: “ARMOR”,
“name”: { “str”: “pair of jika tabi” },
“category”: “armor”,
“description”: " a pair of short boots with splitted toes .",
“weight”: “200 g”,
“volume”: “2000 L”,
“price”:0 ,
“material”: [ “cotton”, “leather” ],
“symbol”: “[”,
“color”: “black”,
“covers”: [ “FEET” ],
“coverage”: 90,
“encumbrance”: 10,
“warmth”:15 ,
“material_thickness”:2 ,
“flags”: [ “ONLY_ONE”, “VARSIZE” ]

It has a volume of 2000 L but one tile can only store 1000 L*.
Did you meant to write 2000 ml (2 L)?

*Unless it’s a Bookcase or something.

ho my god im so retarded thanks, also sorry to have wasted some time

No problem, you’re welcome. Stuff like this is never a waste of time - it just happens and we are (or at least I am) here to help. Also, it took me 1 minute to write that message; given that we have a “please stay at home” direction at the place I live, I now still have to somehow “waste” about 359 more minutes of this day…

They’re obviously disappearing because they’re NINJA shoes.