Cannot query field on type error - Gatsby/Sanity integration issue

Based on the Slack thread context and this being a Gatsby-specific GraphQL error, this is almost certainly a schema synchronization issue between Sanity and Gatsby. Here's how to fix it:

The Root Cause

The "Cannot query field [field] on type [type]" error in Gatsby with gatsby-source-sanity happens when Gatsby's GraphQL schema doesn't match your current Sanity schema. This typically occurs when:

1. You've updated your Sanity schema but haven't redeployed the GraphQL API
2. Gatsby has cached an old version of your schema
3. The GraphQL API deployment failed or is incomplete

Solutions to Try (in order)

1. Redeploy Your Sanity GraphQL API

Every time you update your Sanity schema, you need to redeploy the GraphQL API. From your Sanity Studio folder, run:

sanity graphql deploy

This is the most common fix - the GraphQL endpoint doesn't automatically update when you change your schema.

2. Clear Gatsby's Cache

After redeploying, clear Gatsby's cache to force it to fetch the new schema:

gatsby clean
gatsby develop

This removes the .cache and public folders and forces Gatsby to rebuild everything from scratch.

3. Verify Your gatsby-config.js

Make sure your gatsby-source-sanity plugin configuration is correct:

{
  resolve: 'gatsby-source-sanity',
  options: {
    projectId: 'your-project-id',
    dataset: 'your-dataset',
    // If using drafts or private datasets:
    token: process.env.SANITY_READ_TOKEN,
    watchMode: true, // for development
    overlayDrafts: true, // if previewing drafts
  }
}

4. Check for Field Name Mismatches

The error message should tell you which field is problematic. Verify that:

• The field exists in your Sanity schema
• The field name in your GraphQL query matches exactly (case-sensitive)
• If querying _raw fields (like _rawBody), these are special Gatsby-specific fields that only work with gatsby-source-sanity, not in Sanity's GraphQL playground

Why This Happens

The gatsby-source-sanity plugin works by fetching GraphQL Schema Definitions from Sanity's deployed GraphQL API. If that deployed schema is out of sync with your actual schema or with what Gatsby has cached, you'll get field query errors.

If you're still stuck after trying these steps, share the specific field name and type from your error message for more targeted troubleshooting!