SMTP协议500错误：语法错误

Question

我使用Spring发送附件电子邮件并运行我捕获以下异常

org.springframework.mail.MailSendException: Failed messages: com.sun.mail.smtp.SMTPSendFailedException: 500 Error: bad syntax
; message exception details (1) are:
Failed message 1:
com.sun.mail.smtp.SMTPSendFailedException: 500 Error: bad syntax

at com.sun.mail.smtp.SMTPTransport.issueSendCommand(SMTPTransport.java:1388)
at com.sun.mail.smtp.SMTPTransport.mailFrom(SMTPTransport.java:959)
at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:583)
at org.springframework.mail.javamail.JavaMailSenderImpl.doSend(JavaMailSenderImpl.java:424)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:346)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:341)
at com.synergy.mall.email.Shop30RebateSender.sendShop30RebateEmail(Shop30RebateSender.java:38)
at com.test.Shop30RebateSenderTest.sendShop30RebateEmail(Shop30RebateSenderTest.java:36)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:72)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:81)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:216)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:82)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:60)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:67)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:162)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

春豆：

<bean id="mailSender"     class="org.springframework.mail.javamail.JavaMailSenderImpl">
  <property name="host" value="smtp.***.com" />
    <property name="protocol" value="smtp" />
    <property name="username" value="********" />
    <property name="password" value="********" />
    <property name="javaMailProperties">
        <props>
            <prop key="mail.smtp.auth">true</prop>
            <prop key="mail.smtp.starttls.enable">true</prop>
        </props>
    </property>
</bean>

发送电子邮件方式：

public void sendAttachment(String fileName) {
    try {
        MimeMessage message = aliMailSender.createMimeMessage();
        MimeMessageHelper helper = new MimeMessageHelper(message, true);
        helper.setTo("*****@***.com");
        helper.setText("This is message body");
        FileSystemResource file = new FileSystemResource(new File(fileName));
        helper.addAttachment("file.docx", file);
        this.sender.send(message);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

例外是什么情况？如何解决它？

更新

没有设置原因错误，如下所示：

public void sendAttachment(String fileName) {
    try {
        MimeMessage message = aliMailSender.createMimeMessage();
        MimeMessageHelper helper = new MimeMessageHelper(message, true);
        helper.setFrom("*****@***.com");//No set from cause error
        helper.setTo("*****@***.com");
        helper.setText("This is message body");
        FileSystemResource file = new FileSystemResource(new File(fileName));
        helper.addAttachment("file.docx", file);
        this.sender.send(message);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

我setFrom()，它发送成功。