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

Question

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

Chad Lansford 20

Using Chrome, I was previously able to view data in my Cosmos Databases using the Data Explorer in Azure. However, ever since the Azure outage on October 29th, 2025, the data never loads - it just spins. In the browser console, I can see that I'm getting the following error over and over again:

Access to fetch at 'https://[name-of-cosmos-db].documents.azure.com/' from origin 'https://cosmos.azure.com' has been blocked by CORS policy: Permission was denied for this request to access the unknown address space.

It is only affecting me in Chrome. The data loads fine using the Edge browser.

I've tried clearing my cookies/cache, restarting the browser, but nothing works.

Thomas 0 Reputation points

2025-11-03T09:16:39.2366667+00:00

Got he same issue here:

Brave 1.84.132 (Official Build) (64-bit)

Chromium: 142.0.7444.60

Chrome

Version 142.0.7444.60 (Official Build) (64-bit)

Regardless of what I'm doing. Cleaned DNS, configured different public DNS providers, added '*' to the CORS Policy, completely fresh user profiles on both browsers and clean log-in using incognito mode including all the suggestion above. Nothing works.
Swapnesh Panchal 1,540 Reputation points Microsoft External Staff Moderator

2025-11-04T18:30:12.1+00:00

Hi Thomas,
Could you please raise a new question on Q&A? This will help improve visibility and ensure the issue gets proper attention

Answer accepted by question author

2 additional answers

Your answer

Thomas 0 Reputation points

2025-11-03T09:16:39.2366667+00:00

Got he same issue here:

Brave 1.84.132 (Official Build) (64-bit)

Chromium: 142.0.7444.60

Chrome

Version 142.0.7444.60 (Official Build) (64-bit)

Regardless of what I'm doing. Cleaned DNS, configured different public DNS providers, added '*' to the CORS Policy, completely fresh user profiles on both browsers and clean log-in using incognito mode including all the suggestion above. Nothing works.
Swapnesh Panchal 1,540 Reputation points Microsoft External Staff Moderator

2025-11-04T18:30:12.1+00:00

Hi Thomas,
Could you please raise a new question on Q&A? This will help improve visibility and ensure the issue gets proper attention

Answer 1

Chlanda, Patryk (ext) 85

What you need to change in your Chrome browser (for other chromium browsers it's similar)

-> got to chrome://flags/

-> set the "Local Network Access Checks" flag (#local-network-access-check) to Disabled.

What This Does

This flag controls Chrome's Private Network Access (PNA) policy, which:

When Enabled (Default): Chrome blocks public websites (like https://cosmos.azure.com) from making requests to private/local network resources (like your CosmosDB endpoint https://<my_cosmos_account_name>.documents.azure.com/) without explicit permission
When Disabled : Chrome will no longer enforce these security restrictions, allowing the Azure Cosmos DB portal to access your database endpoint

This was Chrome's PNA protection blocking the request. By disabling this check, Chrome will now allow the cross-network request to proceed.

Important Notes

⚠️ You need to restart Chrome for this change to take effect

⚠️ Security Implications: Disabling this flag reduces browser security by allowing public websites to access private network resources. This is acceptable for development/testing, but be aware of the security trade-off.

Manoj Kumar Boyini 1,660 Reputation points Microsoft External Staff Moderator

2025-11-07T05:43:00.7+00:00

Hi Chad Lansford,

Please try the fix suggested by Chlanda, Patryk (ext): open chrome://flags/, find Local Network Access Checks (#local-network-access-check) and set it to Disabled, then restart Chrome. This flag controls Chrome’s Private Network Access (PNA) checks, which are currently blocking requests from the Azure Data Explorer to your Cosmos DB endpoint and causing the CORS error.

Disabling the flag will let the Data Explorer load data in Chrome, but note that this reduces browser security because public sites can access private network resources. Use this only for troubleshooting or short-term work and re-enable the flag afterwards.

Also keep in mind this started after recent Chrome updates tightening PNA/CORS enforcement and it is not an Azure service outage. As alternatives or additional checks, try Microsoft Edge, update Chrome to the latest build, test in an incognito session with extensions disabled, allow third-party cookies for portal.azure.com and cosmos.azure.com, and clear site data for cosmos.azure.com and *.documents.azure.com. If a corporate proxy, VPN, or SSL inspection is in use, ask IT to whitelist *.documents.azure.com and *.cosmos.azure.com and avoid address rewriting or deep packet inspection for these domains.

If the issue continues, please share Chrome version, a screenshot or capture from DevTools (Network tab) showing the blocked request, and any proxy/VPN details.

Hope this helps. Do let us know if you have any further queries.
Raghavendra 20 Reputation points

2025-11-07T18:42:24.1033333+00:00

Thank you Patryk! Your suggestion worked (Local Network Access Checks)
Chad Lansford 20 Reputation points

2025-11-07T19:22:13.53+00:00

Thanks Patryk, that did the trick!

Answer 2

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:

Update Chrome to the latest build. A recent Chrome update tightened PNA/CORS and a couple of builds caused false “unknown address space” blocks.
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).
Allow third-party cookies for these sites (Chrome → Settings → Privacy & security → Cookies):
- portal.azure.com
- cosmos.azure.com
- login.microsoftonline.com / microsoftonline.com
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”
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.
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.

Swapnesh Panchal 1,540 Reputation points Microsoft External Staff Moderator

2025-11-04T18:31:03.56+00:00

Hi Chad Lansford ,
I hope this is helpful! Do not hesitate to let me know if you have any other questions or clarifications.
Chad Lansford 20 Reputation points

2025-11-04T19:08:41.1033333+00:00

Hi Swapnesh,

I've tried all your suggested updates, but it's still not working for me in Chrome. I'm also having other members of my team experiencing the same thing.

When I look at the network traffic in DevTools, I'm seeing the following Chrome version information: "Chromium";v="142", "Google Chrome";v="142", "Not_A Brand";v="99". Both the preflight and the fetch are being blocked.
Krizan, Steve 0 Reputation points

2025-12-10T17:00:19.3+00:00

FYI, the latest versions of Edge do not work now either as they have similar Private Network Access/CORS checks.
VRISHABHANATH PATIL 2,305 Reputation points Microsoft External Staff Moderator

2025-12-11T04:48:14.05+00:00

Hi @Krizan, Steve

Since the previously reported issue has been resolved with the provided solution, please create a new QA ticket with all the required details. Our team will be happy to assist further. Thank you.

Answer 3

Joaquin Pretell ADM Internal 0

Hello if this open i ahve the same problem with Microsoft Edge Version 143.0.3650.75 (Official build) (64-bit)

VRISHABHANATH PATIL 2,305 Reputation points Microsoft External Staff Moderator

2025-12-12T01:26:00.0866667+00:00

Hi @Joaquin Pretell ADM Internal

Since the previously reported issue has been resolved with the provided solution, please create a new QA ticket with all the required details. Our team will be happy to assist further. Thank you.

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

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