Could not establish EventSource connection error when loading items

The "Could not establish EventSource connection" error you're seeing typically indicates a problem with the real-time connection between your Sanity Studio and the Content Lake. This connection is used to keep your Studio updated with live changes.

Here's what could be causing this:

1. Check Sanity's Status First, verify if there's an ongoing incident by checking status.sanity.io. If there's platform-wide degraded performance or an outage, this would explain the EventSource connection failures.

2. Common Causes (if no outage):

• Network/Firewall Issues: EventSource connections use Server-Sent Events (SSE) which some corporate firewalls, VPNs, or network proxies may block. Try from a different network or disable your VPN temporarily.

• Browser Extensions: Ad blockers or privacy extensions can interfere with EventSource connections. Try disabling them or testing in an incognito/private window.

• CORS/Connection Limits: If you have many Studio tabs open or long-running connections, you might hit browser connection limits. Try closing other tabs and refreshing.

• Local Development Issues: If running locally, ensure your Studio is properly configured and you're authenticated. Try running sanity login again.

3. Immediate Workarounds:

• Refresh your browser (hard refresh with Ctrl+Shift+R or Cmd+Shift+R)
• Clear browser cache and cookies for your Studio
• Try a different browser
• Restart your local dev server if running Studio locally

4. If the Problem Persists:

The Studio should still be functional even without the EventSource connection - you just won't see real-time updates from other users. You can still create, edit, and publish content, but you'll need to manually refresh to see changes from others.

If you're experiencing this consistently and it's not related to a platform incident, reach out to Sanity support through the help center with details about your environment (browser, network setup, whether it's local or deployed Studio).