RabbitTemplate Error: The ApplicationContext is closed and the ConnectionFactory can no longer create connections

I'm using Springboot 1.5.3 and amqp-client 4.0.2.

I have a producer that works fine most of the time, but once in a while I get the following error:

java.lang.IllegalStateException: The ApplicationContext is closed and the ConnectionFactory can no longer create connections.
    at org.springframework.amqp.rabbit.connection.CachingConnectionFactory.createConnection(CachingConnectionFactory.java:561) ~[spring-rabbit-1.7.2.RELEASE.jar!/:na]
    at org.springframework.amqp.rabbit.core.RabbitTemplate.doExecute(RabbitTemplate.java:1430) ~[spring-rabbit-1.7.2.RELEASE.jar!/:na]
    at org.springframework.amqp.rabbit.core.RabbitTemplate.execute(RabbitTemplate.java:1411) ~[spring-rabbit-1.7.2.RELEASE.jar!/:na]
    at org.springframework.amqp.rabbit.core.RabbitTemplate.send(RabbitTemplate.java:712) ~[spring-rabbit-1.7.2.RELEASE.jar!/:na]
    at org.springframework.amqp.rabbit.core.RabbitTemplate.convertAndSend(RabbitTemplate.java:813) ~[spring-rabbit-1.7.2.RELEASE.jar!/:na]
    at org.springframework.amqp.rabbit.core.RabbitTemplate.convertAndSend(RabbitTemplate.java:803) ~[spring-rabbit-1.7.2.RELEASE.jar!/:na]  
    at com.my.amqp.producer.MyProducer.produce(MyProducer.java:16) ~[classes!/:0.6.0-SNAPSHOT]

Here's the class that calls RabbitTemplate.convertAndSend from the produce(...) method:

import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;

public class MyProducer {
    @Value("${rabbit.exchange.in.name}")
    public String exchangeNameIn;

    @Autowired
    RabbitTemplate rabbitTemplate;

    public void produce(String messageToBeDelivered, String routingKey, int messageDelay) throws Exception {
        if (messageDelay > 0) {
            rabbitTemplate.convertAndSend(exchangeNameIn, routingKey, messageToBeDelivered,
                m -> {
                    m.getMessageProperties().setCorrelationId("test-id".getBytes());
                    m.getMessageProperties().setHeader("x-delay", messageDelay);
                    return m;
                });
        } else {
            rabbitTemplate.convertAndSend(exchangeNameIn, routingKey, messageToBeDelivered,
                m -> {
                    m.getMessageProperties().setCorrelationId("test-id".getBytes());
                    return m;
                });
        }
    }
}

The properties associated with rabbitmq:

spring.rabbitmq.listener.concurrency=5
spring.rabbitmq.listener.max-concurrency=5