sudden gmail smtp authentication failure when using app password

Question

So I am trying to set up a spring boot app to send out automated emails. I have created a gmail account specifically for this purpose. I followed a tutorial which directed me to set up two factor authentication for my gmail account, and set up an app password to login. I did this and everything worked fine, I sent a test email from the app and it worked. HOWEVER without making any code changes I tried the proccess again a few hours later and I got the following message:

Exception in thread "main" org.springframework.mail.MailAuthenticationException: Authentication failed; nested exception is javax.mail.AuthenticationFailedException: 534-5.7.9 Please log in with your web browser and then try again. Learn more at
534 5.7.9  https://support.google.com/mail/?p=WebLoginRequired v8-20020a05683018c800b005cb39fc3e15sm11417144ote.13 - gsmtp

Here is my application.properties file:

spring.mail.protocol=smtp
spring.mail.host=smtp.gmail.com
spring.mail.port=587
spring.mail.username=
spring.mail.password=
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true
mail.smtp.debug=true

and here is my mail service (although this error occurs at app startup so I dont think its the cause)


@Service("mailService")
public class MailServiceImpl implements MailService {

    @Autowired
    private JavaMailSender mailSender;

    public void sendEmail(Mail mail) {
        MimeMessage mimeMessage = mailSender.createMimeMessage();

        try {

            MimeMessageHelper mimeMessageHelper = new MimeMessageHelper(mimeMessage, true);

            mimeMessageHelper.setSubject(mail.getMailSubject());
            mimeMessageHelper.setFrom(new InternetAddress(mail.getMailFrom(), "tyler"));
            mimeMessageHelper.setTo(mail.getMailTo());
            mimeMessageHelper.setText(mail.getMailContent());

            mailSender.send(mimeMessageHelper.getMimeMessage());

        } catch (MessagingException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
    }

}

I have tried following the link for advice but it recommends I use an app password (which I already am) or to enable "less secure apps" (which I cant as a 2FA user). Any help would be greatly appreciated.

sudden gmail smtp authentication failure when using app password

0 Answers0