Can't reach Sanity API after standard init with blog preset

This is a frustrating error but usually has a straightforward fix! The "An error occurred while attempting to reach the Sanity API" message typically points to a CORS configuration issue, not an actual API outage.

Here's what to try:

1. Add localhost to your CORS origins

Since you just initialized the project, your localhost development URL likely isn't whitelisted yet. You need to add it in your project settings:

1. Go to manage.sanity.io
2. Select your project
3. Navigate to Settings → API → CORS Origins
4. Click Add CORS origin
5. Add http://localhost:3333 (or whatever port your Studio is running on)
6. Important: Check the "Allow credentials" box
7. Save

The "Allow credentials" checkbox is crucial - without it, you'll still get CORS errors even with the origin added.

2. Use sanity dev instead of sanity start

In modern Sanity projects (Studio v3+), the recommended command is sanity dev, not sanity start. The dev command starts a development server with live reloading and better performance. Try:

npm run dev
# or
sanity dev

3. Check if it's actually an API issue

While rare, sometimes there are actual API issues. You can verify the Sanity API status at status.sanity.io to rule out platform-wide problems.

4. Try the CLI CORS command

You can also add CORS origins via the CLI:

sanity cors add http://localhost:3333 --credentials

The --credentials flag is equivalent to checking that "Allow credentials" box in the dashboard.

Why this happens

When you initialize a new project, Sanity doesn't automatically whitelist localhost URLs for security reasons. Your browser blocks the requests because the Studio (running on localhost) is trying to make authenticated requests to the Sanity API without proper CORS configuration.

The CORS settings you configure in the Management Dashboard control which domains can access your project data with credentials, so this is a necessary security step for any new project.

Give the CORS configuration a try first - that fixes this issue 99% of the time!