我正在使用gmail smtp主机t通过spring boot和JavaMail Sender发送邮件：

我的邮件属性：

 spring.mail.host = smtp.gmail.com
 spring.mail.username = XXX@gmail.com
 spring.mail.password = XXX

 spring.mail.properties.mail.smtp.auth = true
 spring.mail.properties.mail.smtp.socketFactory.port = 465
 spring.mail.properties.mail.smtp.starttls.enable = true
 spring.mail.properties.mail.smtp.socketFactory.class = javax.net.ssl.SSLSocketFactory
 spring.mail.properties.mail.smtp.socketFactory.fallback = false

出现错误：

Failed message 1: javax.mail.MessagingException: Could not connect to SMTP host: smtp.9business.fr, port: 25, response: 421] with root cause

即使我正在使用端口465，为什么他仍指向端口25？