Azure Storage Management Client authentication failure

Question

Using the Azure management APIs to access a storage account I use TokenCloudCredentials for authentication. This works fine for storage accounts under Resource Management but not for Classic storage accounts.

When trying to execute any method on a classic storage account client using TokenCloudCredentials I received this error message:

ForbiddenError: The server failed to authenticate the request. Verify that the certificate is valid and associated with this subscription.

Now for the code- Working method for Azure Resource Manager

var clientId = "{clientID}";
var tenant = "{tenant GUID}";
var pw = "{password}";
var authenticationContext = new AuthenticationContext("https://login.windows.net/" + tenant);
var credential = new ClientCredential(clientId , pw);
Task<AuthenticationResult> tskGetToken = authenticationContext.AcquireTokenAsync(resource: "https://management.core.windows.net/", credential);
        AuthenticationResult token = tskGetToken.Result;
SubscriptionCloudCredentials creds = new TokenCloudCredentials("{subscription id}", token.AccessToken);
StorageManagementClient smc = new StorageManagementClient(creds);
Task<StorageAccountListKeysResponse> tskTargetKeysSource = smc.StorageAccounts.ListKeysAsync("{resource group}", "{storage account name");
            while (tskTargetKeysSource.Status != TaskStatus.RanToCompletion)
            {
                if (tskTargetKeysSource.Exception != null)
                    throw tskTargetKeysSource.Exception;
                Console.WriteLine("Running - Getting target storage account Storage Key");
                Thread.Sleep(2500);
            }

This works and I receive the storage keys back.

Broken method for Azure Classic Storage:

var clientId = "{clientID}";
var tenant = "{tenant GUID}";
var pw = "{password}";
var authenticationContext = new AuthenticationContext("https://login.windows.net/" + tenant);
var credential = new ClientCredential(clientId , pw);
Task<AuthenticationResult> tskGetToken = authenticationContext.AcquireTokenAsync(resource: "https://management.core.windows.net/", credential);
        AuthenticationResult token = tskGetToken.Result;
SubscriptionCloudCredentials creds = new TokenCloudCredentials("{subscription id}", token.AccessToken);
Microsoft.WindowsAzure.Management.Storage.StorageManagementClient classicSmc = new Microsoft.WindowsAzure.Management.Storage.StorageManagementClient(creds);
Task<StorageAccountGetKeysResponse> tskSourceKeysSource = classicSmc.StorageAccounts.GetKeysAsync("{storage account name}", new CancellationToken());
            while (tskSourceKeysSource.Status != TaskStatus.RanToCompletion)
            {
                if (tskSourceKeysSource.Exception != null)
                    throw tskSourceKeysSource.Exception;  // Exception thrown here
                Console.WriteLine("Running - Getting source storage account Storage Key");
                Thread.Sleep(2500);
            }

I am not sure what the difference is. The application that I am writing has proper permission in Azure Active directory and it has permissions on the appropriate resources (storage accounts, resource groups etc.). These operations are using the same subscription as well.