Product Metafields don't update with GraphiQL

Retired Boards Appdev Metafields
17

hey mate, I’m sending this mutation:

mutation {
  productUpdate(input: {
    id: "gid://shopify/Product/6653113303204",
    title: "zinc test",
    metafields: [
      {
        namespace: "global",
        key: "title_tag",
        value: "zinc test",
        valueType: STRING
      }
    ]
  }) {
    product {
      id
      metafields(first: 10, after: null) {
        edges {
          node {
            key
            namespace
            value
          }
        }
      }
    }
    userErrors {
      field
      message
    }
  }
}

and getting this response:

{
  "data": {
    "productUpdate": {
      "product": {
        "id": "gid:\/\/shopify\/Product\/6653113303204",
        "metafields": {
          "edges": []
        }
      },
      "userErrors": []
    }
  },
  "extensions": {
    "cost": {
      "requestedQueryCost": 22,
      "actualQueryCost": 12,
      "throttleStatus": {
        "maximumAvailable": 1000.0,
        "currentlyAvailable": 988,
        "restoreRate": 50.0
      }
    }
  }
}

I’m trying to create the metafield