title: The constraint entry 'inboundHttpMethod' must have a string value or be of a type which implements 'IHttpRouteConstraint
body: <p>I am trying to implement attribute routing, but getting following error.</p>
  
  <blockquote>
    <p>The constraint entry 'inboundHttpMethod' on the route with route
    template 'authenticate' must have a string value or be of a type which
    implements 'IHttpRouteConstraint</p>
  </blockquote>
  
  <p>I already added the line of code in Global.asax,  </p>
  
  <pre><code>    AttributeRoutingHttpConfig.RegisterRoutes(GlobalConfiguration.Configuration.Routes);
  </code></pre>
  
  <p>and the below code in AttributeRoutingHttpConfig.cs, </p>
  
  <pre><code>routes.MapHttpAttributeRoutes(cfig =&gt;
              {
                  cfig.UseLowercaseRoutes = true;
                  cfig.AutoGenerateRouteNames = true;
                  cfig.AddRoutesFromAssemblyOf&lt;AuthenticateController&gt;();
                  cfig.InMemory = true;
              });
  </code></pre>
  
  <p>Anyone know about the issue, actually I am new to c#.</p>