By sending an email I got the following exception:

org.springframework.mail.MailSendException: Failed messages: com.sun.mail.smtp.SMTPSendFailedException: 530 5.7.0 Must issue a STARTTLS command first. b10sm22671312wmi.34 - gsmtp

Here is the code that I'm using for sending email:

MailRequest mailRequest = new MailRequest();
mailRequest.setSubject(messageByLocale.getMessage("mail.subject.forgetpassword"));
mailRequest.setTemplateName(messageByLocale.getMessage("mail.template.forgetpassword"));
mailRequest.setToEmail(tbNstyleloyalty.getEmail());
Map<String, Object> map = new HashMap<>();
map.put("tbNstyleloyalty", tbNstyleloyalty);
mailingConfig.sendEmail(mailRequest, map);

And my sendEmail method is:

@Async
public void sendEmail(MailRequest mailRequest, Map<String, Object> model) {
    MimeMessagePreparator preparator = new MimeMessagePreparator() 
    {
        @Override
        public void prepare(MimeMessage mimeMessage) throws Exception {
                MimeMessageHelper message = new MimeMessageHelper(mimeMessage);
                message.setTo(mailRequest.getToEmail());
                message.setSubject(mailRequest.getSubject());
                message.setText(VelocityEngineUtils.mergeTemplateIntoString(velocityEngine,templatePath + mailRequest.getTemplateName() + ".vm", ApplicationConstants.CHARSET_UTF8, model),true);
         }
    };
    this.javaMailSender.send(preparator);
}

Please, help me to overcome from this issue.

Thank you!