title: Role Based Authorization Identity API - registration not working
body: <p>I have been following a Youtube video: <a href="https://www.youtube.com/watch?v=IBpZCFbjvA0" rel="nofollow noreferrer">https://www.youtube.com/watch?v=IBpZCFbjvA0</a>
  to use the identity API to create role-based users for my asp.net core web app. The role creates and stores successfully in my database but I get an error trying to register a user.</p>
  
  <p>The error is:
  An unhandled exception occurred while processing the request. ArgumentNullException: Value cannot be null. Parameter name: items Microsoft.AspNetCore.Mvc.Rendering.MultiSelectList..ctor(IEnumerable items, string dataValueField, string dataTextField, IEnumerable selectedValues, string dataGroupField).</p>
  
  <p>I have a public github repository along with the full error in the readme.
  <a href="https://github.com/tripiod8/AUTHORIZATION_EXERCISE3.git" rel="nofollow noreferrer">https://github.com/tripiod8/AUTHORIZATION_EXERCISE3.git</a></p>
  
  <p>I'm new to learning ASP and I would really appreciate if anybody could explain to me why one of list fields is null.  </p>
  
  <p>Thank you very much!</p>