how to connect to PowerBI using C#

[v-wuling]

I follow the article: https://powerbi.microsoft.com/en-us/documentation/powerbi-developer-authenticate-a-web-app/, download the sample http://go.microsoft.com/fwlink/?LinkId=619279,when I run the project in VS, I get the error :

An exception of type 'Microsoft.IdentityModel.Clients.ActiveDirectory.AdalServiceException' occurred in Microsoft.IdentityModel.Clients.ActiveDirectory.dll but was not handled in user code

Additional information: AADSTS70000: Authentication failed: Authorization Code is malformed or invalid.

Trace ID: b83ddc21-a4e0-4013-80c7-23253397e619

Correlation ID: f305fc18-aefd-40d0-a71d-8c278a7abbb5

Timestamp: 2016-03-02 08:47:54Z

Who can tell me the solution? Appreciate.