Connecting to Azure Blob Storage using Client Credential from on-premise

Question

I'm trying to interact with an Azure Blob Storage protected by Azure AD using ClientID & ClientSecret. It's working fine when I'm running the application from my machine on Visual Studio however when I run it from a VM on-premise, I'm getting this error:

An error response was returned by the OAuth2 server, but it could not be parsed. Please inspect the exception properties for details. ---> MSAL.NetCore.4.30.1.0.MsalServiceException: ErrorCode: non_parsable_oauth_error Microsoft.Identity.Client.MsalServiceException: An error response was returned by the OAuth2 server, but it could not be parsed. Please inspect the exception properties for details. at Microsoft.Identity.Client.Internal.Requests.RequestBase.HandleTokenRefreshError(MsalServiceException e, MsalAccessTokenCacheItem cachedAccessTokenItem) at Microsoft.Identity.Client.Internal.Requests.ClientCredentialRequest.ExecuteAsync(CancellationToken cancellationToken) at Microsoft.Identity.Client.Internal.Requests.RequestBase.RunAsync(CancellationToken cancellationToken) at Microsoft.Identity.Client.ApiConfig.Executors.ConfidentialClientExecutor.ExecuteAsync(AcquireTokenCommonParameters commonParameters, AcquireTokenForClientParameters clientParameters, CancellationToken cancellationToken) at Azure.Identity.AbstractAcquireTokenParameterBuilderExtensions.ExecuteAsync[T](AbstractAcquireTokenParameterBuilder`1 builder, Boolean async, CancellationToken cancellationToken) at Azure.Identity.MsalConfidentialClient.AcquireTokenForClientAsync(String[] scopes, Boolean async, CancellationToken cancellationToken) at Azure.Identity.ClientSecretCredential.GetTokenAsync(TokenRequestContext req uestContext, CancellationToken cancellationToken) StatusCode: 407

Answer 1

Looks like you are going through a proxy to access the Oauth endpoint

https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/407

The HTTP 407 Proxy Authentication Required client error status response code indicates that the request has not been applied because it lacks valid authentication credentials for a proxy server that is between the browser and the server that can access the requested resource.

You need to inspect the connectivity properties between the VM and the OAuth server