<Error><Message>An error has occurred.</Message><ExceptionMessage>Object reference not set to an instance
 of an object.</ExceptionMessage><ExceptionType>System.NullReferenceException</ExceptionType><StackTrace
>   at Mercurian.EduCRM.Web.Api.Controllers.EnrolmentController.Add(EnrolmentEditModel model) in c:\work
\aspnet\educrm\code\Mercurian.EduCRM.Web.Api\Controllers\EnrolmentController.cs:line 48
   at lambda_method(Closure , Object , Object[] )
   at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.&lt;&gt;c__DisplayClass13
.&lt;GetExecutor&gt;b__c(Object instance, Object[] methodParameters)
   at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance
, Object[] arguments)
   at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.&lt;&gt;c__DisplayClass5.&lt;ExecuteAsync
&gt;b__4()
   at System.Threading.Tasks.TaskHelpers.RunSynchronously[TResult](Func`1 func, CancellationToken cancellationToken
)</StackTrace></Error>