Why does this enchantment attribute not work?

[charred wave]

  "description": "Fortified",
  "supported_items": "#minecraft:enchantable/armor",
  "weight": 1,
  "max_level": 2,
  "min_cost": {
    "base": 15,
    "per_level_above_first": 15
  },
  "max_cost": {
    "base": 65,
    "per_level_above_first": 15
  },
  "anvil_cost": 2,
  "slots": [],
  "effects": {
    "minecraft:attributes": [
      {
        "attribute": "minecraft:armor_toughness",
        "id": "restructure:enchantment.fortified",
        "amount": {
          "type": "minecraft:linear",
          "base": 1,
          "per_level_above_first": 1
        },
        "operation": "add_value"
      }
    ]
  }
}```

[charred wave]

As seen here, it does not add armor toughness

Oh

I forgot slots: armor