问为什么某些或所有身份引用无法翻译？

EN

Microsoft.Expression.Encoder.Preset pres = Microsoft.Expression.Encoder.Presets.VC1IISSmoothStreamingSD480pVBR;

Server Error in '/' Application.
some or all identity references could not be translated
  Description: An unhandled exception occurred during the execution of the current web request. Examine the stack trace for more information about this error and where it originated in the code.

  Exception Details: System.Security.Principal.IdentityNotMappedException: some or all identity references could not be translated.

var job = new Job();

using System;
using System.Linq;
using System.Web.Mvc;
using Microsoft.Expression.Encoder;
using Microsoft.Expression.Encoder.Profiles;
using VideoSmooth.Domain.Abstract;
using VideoSmooth.Domain.Entities;
using VideoSmooth.Web.Models;