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Fixing Azure Key Vault "Data Plane Connection Failed" Error

Christopher Talke Buscaino

This article was created with AI to ensure this solution is discoverable for those struggling with this issue. Credit goes to contributors in this reddit thread and my colleague Frank for identifying the fix for our own needs.

If you're encountering a persistent "connection to data plane failed. Please refresh and try again" error while accessing Azure Key Vault secrets, keys, or certificates, the root cause may not be your network configuration.

The Problem

When using Azure Key Vault via the Azure Portal, you may encounter:

  • Repeated "The connection to data plane failed" errors
  • References to private links, even with unrestricted public access enabled
  • Inconsistent behavior when refreshing the page
  • Failures that persist regardless of private endpoint settings

If some users in your organization can access Key Vault while others cannot, this points to a browser configuration issue.

Enable Local Network Access in Your Browser

The solution requires enabling "Local Network Access" in your browser settings. Follow these steps for your browser:

Google Chrome

  1. Open the Azure Portal (portal.azure.com)
  2. Click the lock icon (or site settings icon) left of the URL
  3. Enable "Local network access"
  4. Refresh the page

Microsoft Edge

  1. Open the Azure Portal (portal.azure.com)
  2. Navigate to Settings > Privacy, search, and services
  3. Scroll to Site permissions > All permissions
  4. Select Local network access
  5. Under "Allowed to connect to any device on your local network", click Add Site
  6. Add https://portal.azure.com:443
  7. Restart your browser

Alternative Quick Method (Chrome/Edge)

  1. While on the Azure Portal, click the lock/settings icon next to the URL
  2. Look for "Local network access" or "Site settings"
  3. Enable the "Local network access" permission
  4. Restart your browser

Why

When Azure Key Vault is configured with private endpoints, the Azure Portal needs to establish a connection through your local network to reach the private endpoint.

Modern browsers restrict this capability by default as a security measure. By explicitly allowing the Azure Portal to access your local network, you're giving it permission to properly connect to Key Vaults configured with private endpoints.

Interestingly, this issue can occur even with Key Vaults that have unrestricted public access, as the portal may still attempt to use private endpoint connections if they're detected in your environment (e.g. via a Client to Site VPN).

When Did This Become an Issue?

This appears to be a relatively recent change in browser security policies. Multiple users have reported that this worked fine just a few weeks prior, suggesting that browser updates introduced stricter local network access controls that now affect Azure Portal functionality.

Additional Troubleshooting

If enabling local network access doesn't resolve your issue, consider these additional steps (which are outlined here by Microsoft Diagnose private links configuration issues on Azure Key Vault)

  1. Verify Private Endpoint Configuration: If using private endpoints, ensure your DNS configuration is correct and that the private endpoint is properly set up.

  2. Check Network Connectivity: Confirm you can reach the Key Vault from your current network location, if you have specific firewall configurations within your Azure Environment, this will also play a factor.

  3. Clear Browser Cache: Sometimes clearing your browser cache and cookies can help resolve persistent issues.

  4. Try a Different Browser: Test with another browser to rule out browser-specific issues.