Spring mail xml 错误

spring 配置文件如下:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC
    "-//SPRING//DTD BEAN//EN"
    "http://www.springframework.org/dtd/spring-beans.dtd">

<beans default-autowire="no" default-lazy-init="true"
	default-dependency-check="none">

	<bean id="mailSender"
		class="org.springframework.mail.javamail.JavaMailSenderImpl">
		<property name="host">
			<value>mail.footmarktech.com</value>
		</property>
		 <property name="username">
			<value>long.huang@footmarktech.com</value>
		</property>
		<property name="password">
			<value>bing520</value>
		</property>

		<property name="protocol">
			<value>smtp</value>
		</property>
		<property name="javaMailProperties">
			<props>
				<prop key="mail.smtp.auth">true</prop>
				<prop key="mail.smtp.timeout">25000</prop> 
			</props>	
		</property>
	 	</bean>

	<bean id="mailMessage"
		class="org.springframework.mail.SimpleMailMessage">
		<!--  <property name="to"><value></value></property>-->
		<property name="from">
			<value>long.huang@footmarktech.com</value>
		</property>
		<property name="subject">
			<value>RuntimeException</value>
		</property>
	</bean>

	<bean id="mailService"
		class="com.footmark.dating.bean.impl.MailService">
		<property name="mailSender">
			<ref bean="mailSender" />
		</property>
		<property name="mailMessage">
			<ref bean="mailMessage" />
		</property>
	</bean>

</beans>

点发送以后,报:发送失败Failed messages: com.sun.mail.smtp.SMTPSendFailedException: 555 Syntax error

各位高手请指教