How to fix Sign-In failure to Portal.azure.com error code post_request_failed

Hey Brian, it looks like you’re hitting a generic MSAL “post_request_failed” that essentially means the browser couldn’t complete the network call (often due to CORS blockers, proxies or extensions). Since you’re signing into the Azure portal itself—rather than a custom SPA—the usual “redirectUri type” advice doesn’t really apply, so let’s focus on local/network troubleshooting and pulling more data from Entra.

Here’s what you can try right away:

1. Rule out browser caching or extensions

• Open portal.azure.com in a private/incognito window or a different browser (Chrome↔Edge↔Firefox).

• Disable any ad-blockers, privacy/CORS-blocking extensions or strict script-blockers.

2. Check your network path

• If you’re behind a corporate proxy or firewall, confirm it isn’t blocking calls to Microsoft identity endpoints (login.microsoftonline.com, etc.).

• Try from another network (home vs. office) or via a mobile hotspot to see if it’s network-specific.

3. Sync clock & clear DNS cache

• Make sure your PC’s date/time is accurate.

• Run ipconfig /flushdns in a Windows shell (or clear DNS cache on macOS/Linux).

4. Capture the failure details in Entra

• In the Microsoft Entra admin center, go to Entra ID > Monitoring & health > Sign-in logs.

• Filter for failures and find your entry (use your UPN and approximate timestamp).

• Grab the Correlation ID, error code/message and Failure reason.

5. Inspect the browser console

• In Developer Tools (F12), watch the Network tab as you sign in—look specifically for failed requests or CORS errors around the modal post request.

• Note the exact endpoint URL and any HTTP status codes.

If after those steps the portal still won’t let you sign in, please share:

• Browser(s) and version(s) tested

• Whether it works on a different network or machine

• Correlation ID, timestamp and failure details from the Entra sign-in log

• Any extensions or corporate network appliances in play

With that info we can drill in deeper. Hope that helps get you unstuck!

References

1. How to troubleshoot Microsoft Entra sign-in errors

https://learn.microsoft.com/entra/identity/monitoring-health/howto-troubleshoot-sign-in-errors?wt.mc_id=knowledgesearch_inproduct_azure-cxp-community-insider#gather-sign-in-details

2. I am seeing trouble signing in to application(s) using Chrome browser only

https://docs.microsoft.com/office365/troubleshoot/miscellaneous/chrome-behavior-affects-applications

Note: This content was drafted with the help of an AI system. Please verify the information before relying on it for decision-making.

Brian Foley

Following up to see if the above provided information was helpful. If you have any further queries do let us know.

I'm experiencing the same issue. Here are the details you suggested I collect:

1. Rule out browser caching or extensions • Open portal.azure.com in a private/incognito window or a different browser (Chrome↔Edge↔Firefox). • Disable any ad-blockers, privacy/CORS-blocking extensions or strict script-blockers.

I'm experiencing it in MS Edge Version 148.0.3967.70 (Official build) (64-bit). This issue does not happen in a private window, and it does not happen in Chrome.I do not have any ad-blockers, privacy/CORS-blocking extensions or strict script-blockers.

I've cleared the cache and removed the cookies associated with the portal.azure.com site from the browser.

I've cleared the site data from Application > Storage.

This issue does not happen in a private window, and it does not happen in Chrome.

1. Check your network path • If you’re behind a corporate proxy or firewall, confirm it isn’t blocking calls to Microsoft identity endpoints (login.microsoftonline.com, etc.). • Try from another network (home vs. office) or via a mobile hotspot to see if it’s network-specific.

I've tried both on my work and home networks - issue still exists.

1. Sync clock & clear DNS cache • Make sure your PC’s date/time is accurate. • Run ipconfig /flushdns in a Windows shell (or clear DNS cache on macOS/Linux).

Date/time is accurate.

Running ipconfig /flushdns did not fix the issue

1. Capture the failure details in Entra • In the Microsoft Entra admin center, go to Entra ID > Monitoring & health > Sign-in logs. • Filter for failures and find your entry (use your UPN and approximate timestamp). • Grab the Correlation ID, error code/message and Failure reason.

Entra does not show any login failures.

1. Inspect the browser console • In Developer Tools (F12), watch the Network tab as you sign in—look specifically for failed requests or CORS errors around the modal post request. • Note the exact endpoint URL and any HTTP status codes. If after those steps the portal still won’t let you sign in, please share: • Browser(s) and version(s) tested • Whether it works on a different network or machine • Correlation ID, timestamp and failure details from the Entra sign-in log • Any extensions or corporate network appliances in play

I see two failed requests:

• Request 1:
  • Request URL https://portal.azure.com/api/telemetry
  • Request Method POST
  • Status Code 401 Unauthorized
  • Referrer Policy strict-origin-when-cross-origin
• Request 2:
  • Request URL https://portal.azure.com/api/telemetry
  • Request Method POST
  • Status Code 401 Unauthorized
  • Referrer Policy strict-origin-when-cross-origin

By the way, this issue just started happening in the past couple of weeks - - before then I was logging into the Azure portal without any issues.

Any ideas on a solution?