Make sure that you are looking at the GraphQL Admin API vs. the GraphQL Storefront API. You will also want to make sure you are using the correct version, although for this attribute it will be in all versions.
But I got an error says:
“Internal error. Looks like something went wrong on our end.\nRequest ID: dc665f52-1f95-4451-8a16-1d6a40ed2d39 (include this in support requests).”
Interesting. Are you using the Shopify GraphiQL app? I am able to replicate the error on a private app intermittently so I will dig into this more and let you know. Using the GraphiQL app from the admin however, I am able to do the query without issue. Keep in mind, this also may not be the navigation you are thinking i.e the theme navigation.