<m:error xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
<m:code/>
<m:message xml:lang="en-US">An error has occurred.</m:message>
<m:innererror>
<m:message>
Exception has been thrown by the target of an invocation.
</m:message>
<m:type>System.Reflection.TargetInvocationException</m:type>
<m:stacktrace>
at System.Web.Http.ApiController.<InvokeActionWithExceptionFilters>d__1.MoveNext()
 --- End of stack trace from previous location where exception was thrown ---
 at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
 at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
 at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
 at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__0.MoveNext()
</m:stacktrace>
<m:internalexception>
<m:message>
Unable to determine the serialization information for the expression: <ConditionalExpression>.
</m:message>
<m:type>System.NotSupportedException</m:type>
<m:stacktrace>
at MongoDB.Driver.Linq.Utils.BsonSerializationInfoFinder.GetSerializationInfo(Expression node, Dictionary`2 serializationInfoCache)
 at MongoDB.Driver.Linq.Utils.BsonSerializationInfoHelper.GetSerializationInfo(Expression node)
 at MongoDB.Driver.Linq.PredicateTranslator.BuildComparisonQuery(Expression variableExpression, ExpressionType operatorType, ConstantExpression constantExpression)
 at MongoDB.Driver.Linq.PredicateTranslator.BuildComparisonQuery(BinaryExpression binaryExpression)
 at MongoDB.Driver.Linq.PredicateTranslator.BuildQuery(Expression expression)
 at MongoDB.Driver.Linq.PredicateTranslator.BuildAndAlsoQuery(BinaryExpression binaryExpression)
 at MongoDB.Driver.Linq.PredicateTranslator.BuildQuery(Expression expression)
 at MongoDB.Driver.Linq.SelectQuery.BuildQuery()
 at MongoDB.Driver.Linq.SelectQuery.Execute()
 at MongoDB.Driver.Linq.MongoQueryProvider.Execute(Expression expression)
 at MongoDB.Driver.Linq.MongoQueryProvider.Execute[TResult](Expression expression)
 at System.Linq.Queryable.LongCount[TSource](IQueryable`1 source)
</m:stacktrace>
</m:internalexception>
</m:innererror>
</m:error>