Cannot view data in the Azure Cosmos DB Data Explorer in Chrome

Hi Chad Lansford ,
Welcome to the Microsoft Q&A and thank you for posting your query.

You’re hitting a Chrome-specific security block, not a Cosmos DB outage. The message

blocked by CORS policy: Permission was denied for this request to access the unknown address space

comes from Chrome’s newer Private Network Access/CORS checks. Edge works because its network policies/extensions differ, so the service itself is fine.

What usually fixes it:

1. Update Chrome to the latest build. A recent Chrome update tightened PNA/CORS and a couple of builds caused false “unknown address space” blocks.
2. Try a clean profile / Incognito with all extensions disabled. If it works there, re-enable extensions one by one (ad-blockers, privacy tools, password managers, recording tools often hook requests).
3. Allow third-party cookies for these sites (Chrome → Settings → Privacy & security → Cookies):
   • portal.azure.com
   • cosmos.azure.com
   • login.microsoftonline.com / microsoftonline.com
4. Clear site data just for cosmos.azure.com and *.documents.azure.com, then reload. Also flush DNS/sockets:
   • chrome://net-internals/#dns → “Clear host cache”
   • chrome://net-internals/#sockets → “Flush sockets”
5. If you’re behind a corporate proxy/VPN/SSL inspection, ask IT to bypass inspection and any PAC rewrites for:
   • *.documents.azure.com
   • *.cosmos.azure.com Some proxies steer these to non-public ranges, which Chrome classifies as “unknown/private” and blocks.
6. As a last resort for local testing only, temporarily relax the PNA block (managed devices may not allow this):
   • chrome://flags → “Block insecure private network requests” → Disabled → relaunch (re-enable after testing).

Workarounds while you fix the browser:

• Use Microsoft Edge (as you noted, it works).
• Use a fresh Chrome profile with no extensions.

If it still fails, capture one failing request in DevTools → Network and note: Chrome version, any proxy/agent in use, and whether the failing entry is a preflight (OPTIONS) blocked by the browser before it reaches *.documents.azure.com. That will confirm it’s a client/policy issue rather than Cosmos DB.