Error "Cannot query field "allSignature" on type "Query"."

Hello,
new to JAMStack decided to follow Smashingmagazine query in https://www.smashingmagazine.com/2020/06/static-sites-jamstack-apps-faunadb/. I set up all according to tutorial but when building (gatsby develop) I keep getting an error

error There was an error in your GraphQL query:

Cannot query field "allSignature" on type "Query".

I have a account on fauna.com. My faunaDb “guestbook” contains a collection “signatures”. I have an index “allSignatures”.
My gatsby-config.js contains this entry for gatsby-source-faunadb:

secret: process.env.GATSBY_FAUNADB_GUESTBOOK_KEY,
index: `allSignatures`,
type: `signature`,

my query:

        graphql`
            query GetSignatures {
                allSignature {
                    nodes {
                        name: String
                        message: String
                        _ts: String
                        _id: String
                    }
                }
            }
        `

I do not know why I am unable to request all field in the collection. According to the docs defining a type signature allows me to use a query allSignature.
This happens when the collection is empty (which is logical for a new db) and when a document with field name and message is added.

Is there a mismatch in the naming of collection / index or in gatsby-config.js type / index properties?

Thanks,

Marc

@Marc, were you able to resolve this? There seems to be a mismatch with the Index naming index: 'allSignatures' and { allSignature { in the query. The easy way to troubleshoot way is to log in to your dashboard, use Webshell to list indexes using Paginate(Indexes()). This should match with the { allSignature { in the query.