Validation error on mesage

For the following code below, if the service of the message handler throws say a validation exception, Do I have to explicitly check the dlq for exceptions? And would a exception cause the handler to retry processing the message?

    using (var mqClient = servicebus.CreateMessageQueueClient())
        mqClient.Publish(new SendEmail { Name = "FromCore" });

        var qname = QueueNames<SendEmailResponse>.In;

        ////Block until the Response is Received:
        var responseMsg = mqClient.Get<SendEmailResponse>(qname);
        mqClient.Ack(responseMsg); //Acknowledge the message was received


The MQ Message Workflow is published on the docs. Have you checked the DLQ to see if your message was sent there?