The mail settings are stored in mail.properties and the beans about mail sender are set in applicationContext-service.xml. They are mailEngine, mainlSender. We don't need to change mailEngine. But we must add a new property for mailSender because the default setting does not support mail authorization in many mail servers. The new property is below:
   <bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
        <property name="host" value="${mail.host}"/>
        <property name="username" value="${mail.username}"/>
        <property name="password" value="${mail.password}"/>
        <property name="javaMailProperties">
           <props>
             <prop key="mail.smtp.auth">true</prop>
           </props>
        </property>
    </bean>
    The red lines are new. we have to add them. Otherwise the mail function in Appfuse does not work.