Field 'translatableResources' doesn't exist on type 'QueryRoot' – Shopify

I installed the Shopify GraphiQL App in my Shopify store to test some GraphQL queries.

I want to translate content via their API.
Here is the documentation for it: https://help.shopify.com/en/api/guides/multi-language/translating-content-api#retrieve-a-list-of-translatable-resource-types

Now, I want to query their first example in the documentation: Retrieve a list of translatable resource types

{
  __type(name: "TranslatableResourceType") {
    enumValues {
      name
    }
  }
}

And received this response:

{
  "data": {
    "__type": null
  }
}

Also the second query isn’t working: Retrieve a list of translatable resources by their type

{
  translatableResources(first: 1, resourceType: PRODUCT) {
    edges {
      node {
        resourceId
        translatableContent {
          key
          value
          digest
          locale
        }
      }
    }
  }
}

The error of the second query:

{
  "errors": [
    {
      "message": "Field 'translatableResources' doesn't exist on type 'QueryRoot'",
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ],
      "path": [
        "query",
        "translatableResources"
      ],
      "extensions": {
        "code": "undefinedField",
        "typeName": "QueryRoot",
        "fieldName": "translatableResources"
      }
    }
  ]
}

When I installed the Shopify GraphiQL App, I picked all permissions (incl. read_translations and write_translations permissions).
And I do have products in my store.

Which setting is missing or what am I doing wrong?