graphql mutations, how to create link field?

Question

I am following this guide. https://drupal-graphql.gitbook.io/graphql/mutations/mutations

I have created a module and with a plain text field I can run

mutation {
  createArticle(data: { title: "https://google.com" }) {
    ... on Article {
      id
      title
    }
  }
}

And it creates an article with title https://google.com.

Now I am trying to add a link field. I have updated the module to write to a link field. I run below

mutation {
  createArticle(data: { link: "https://google.com" }) {
    ... on Article {
      id
      link
    }
  }
}

But link returns empty.

How can I make the mutation write to the link field?

Thanks