I am working on a Sharepoint Application with Office 365. It is an Auto Hosted App and I want to get the file (excel) stream from document library so i can use openXML to perform further operations. I am getting the exception **"The remote server returned an error: (403) Forbidden."**

here is the code: 

```
Microsoft.SharePoint.Client.File file = GetTheFileFromTheDocLibrary("excelfile.xlsx");

            ClientContext clientContext = new ClientContext(Session["SPHostUrl"].ToString());
            FileInformation fInfo = SP.File.OpenBinaryDirect(clientContext, file.ServerRelativeUrl);
            // The remote server returned an error: (403) Forbidden.
            using (MemoryStream memoryStream = new MemoryStream())
            { // other code

```

Note: the same code is working in a Provider Hosted Application.