How to fix this error
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Error code: post_request_failed Error message: post_request_failed:
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Shubham Sharma 17,675 Reputation points • Microsoft External Staff • Moderator
Ducky Army
Thank you for reaching out to Microsoft Q&A.
Could you please provide the complete error message along with a screenshot of the error you are seeing?
This information will help us investigate the issue further and identify the root cause.
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1 answer
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Jose Benjamin Solis Nolasco 8,561 Reputation points • Volunteer Moderator
Welcome to Microsoft Q&A
Hello @Ducky Army I hope you are doing well,
The post_request_failed error is a specific exception thrown by the Azure App Service Authentication (Easy Auth) middleware.
During the OAuth2 authorization code flow, your user authenticates successfully at the identity provider (like Microsoft Entra ID, Google, or GitHub). The provider then redirects the user back to your App Service with an authorization code. Your App Service must then make a server-to-server POST request to the identity provider's token endpoint to exchange that code for an actual access token.
The post_request_failed error means that this backend server-to-server POST request failed. This almost always points to one of three underlying issues:
Expired Client Secret: The client secret configured in your App Service Authentication settings has expired or is invalid. The identity provider rejected the POST request because the App Service could not prove its identity. Remediation: Go to your App Registration in the identity provider, generate a new Client Secret, and update the App Service Authentication configuration with the new value.
Outbound Network Connectivity: If your App Service is integrated with an Azure Virtual Network (VNet Integration) and Route All is enabled, a Network Security Group (NSG) or Firewall might be blocking the outbound HTTPS request to the identity provider. Remediation: Verify your NSG outbound rules allow traffic over port 443 to the AzureActiveDirectory service tag (or the public internet if using a third-party provider).
- Misconfigured Issuer URL: The identity provider endpoint configured in the App Service Authentication settings is incorrect, so the POST request is being sent to a dead URL. Remediation: Double-check the OpenID Connect Issuer URL in your Easy Auth settings.
To find the exact root cause, go to App Service Logs in the Azure Portal, enable Application Logging (Filesystem), and reproduce the error. The log stream will display the inner exception detailing exactly why the POST request was dropped.
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