无法连接到主机，端口：smtp.gmail.com，587；超时-1

Question

我尝试通过Java应用程序发送电子邮件。但无法连接到Gmail主机。 有人可以给我支持吗？它已经可以在家里与我的Eclipse Oxygen一起使用，但是在我在工作中使用的环境中，它总是会失败。非常感谢您的帮助：）

    import java.io.UnsupportedEncodingException;
    import java.util.Properties;

    import javax.mail.Message;
    import javax.mail.MessagingException;
    import javax.mail.PasswordAuthentication;
    import javax.mail.Session;
    import javax.mail.Transport;
    import javax.mail.internet.AddressException;
    import javax.mail.internet.InternetAddress;
    import javax.mail.internet.MimeMessage;


    public class SendMail {

        public static void main(String[] args) {

            final String username = "myemail@gmail.com";
            final String password = "mypassword";

            Properties props = new Properties();
            props.put("mail.smtp.starttls.enable", "true");
            props.put("mail.smtp.auth", "true");
            props.put("mail.smtp.host", "smtp.gmail.com");
            props.put("mail.smtp.port", "587");

            Session session = Session.getInstance(props,
              new javax.mail.Authenticator() {
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(username, password);
                }
              });

            try {

                Message message = new MimeMessage(session);
                message.setFrom(new InternetAddress("myemail@gmail.com"));
                message.setRecipients(Message.RecipientType.TO,
                    InternetAddress.parse("mysendtoemail@outlook.com"));
                message.setSubject("Testbetreff");
                message.setText("Sehr geehrter Herr gng76u76ihn,"
                    + "\n\n Testnachricht");


                    Transport.send(message);


                System.out.println("Done");

            } catch (MessagingException e) {
                throw new RuntimeException(e);
            }
        }
    }