title: No user in signinSilentCallback using identityserver and oidc client of javascript
body: <p>I am getting user undefined in following code. </p>
  
  <p>I have already authenticated user from MVC. </p>
  
  <p>But when I use signinSilentCallback to get detail of that user, it is getting undefined using oidc-client in js. </p>
  
  <p>It doesn't give any error as well.  </p>
  
  <pre><code>        var mgr = new UserManager({
                      authority: "http://localhost:5000",
                      client_id: "js",
                      redirect_uri: "http://localhost:50144/signin-oidc",
                      silent_redirect_uri: "http://localhost:50144/signin-oidc",
                      response_type: "id_token token",
                      post_logout_redirect_uri: "http://localhost:50144/signout-callback-oidc",
                  });
  
          mgr.signinSilentCallback().then(function (user) {
  
              //**Here user is undefined.**
              axios.defaults.headers.common['Authorization'] = "Bearer " + user.access_token;
  
          });
  </code></pre>
  
  <p>In Identityserver 4, client is defined as following.</p>
  
  <pre><code>new Client
                  {
                      ClientId = "js",
                      ClientName = "js",
                      ClientUri = "http://localhost:50144",
  
                      AllowedGrantTypes = GrantTypes.Implicit,
                      AllowAccessTokensViaBrowser = true,
                      RequireClientSecret = false,
                      AccessTokenType = AccessTokenType.Jwt,
  
                      RedirectUris = 
                      {
                          "http://localhost:50144/signin-oidc",
                      },
  
                      PostLogoutRedirectUris = { "http://localhost:50144/signout-callback-oidc" },
                      AllowedCorsOrigins = { "http://localhost:50144" },
  
                      AllowedScopes =
                      {
                          IdentityServerConstants.StandardScopes.OpenId,
                          IdentityServerConstants.StandardScopes.Profile,
                          IdentityServerConstants.StandardScopes.Email
                      }
                  }
  </code></pre>