当端口587被阻塞时，如何用Java发送gmail？

我正在尝试使用587端口和我的Gmail帐户发送电子邮件，下面是代码。如果我在公司网络之外，我的代码工作正常。当我在防火墙/代理后时，它不工作。我也无法ping到smtp.gmail.com。我也试过使用我的公司邮箱id，但问题是一样的

当587被阻止时，有没有办法从防火墙后面发送电子邮件

package otel;
import java.io.IOException;
import java.util.Properties;
import java.util.Timer;
import java.util.TimerTask;

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

public class SendMailTLS {
        public static void main(String[] args) throws IOException {
        int MINUTES = 2; // The delay in minutes
        Timer timer = new Timer();
         timer.schedule(new TimerTask(){
            @Override
            public void run() { // Function runs every MINUTES minutes.
                // Run the code you want here
          //      CLASSB.funcb(); // If the function you wanted was static
            //  System.out.println("This is a timer test");

            // 1000 milliseconds in a second * 60 per minute * the MINUTES variable. 
                System.setProperty("http.proxyHost", "xxxxxxxxxxxxx");
                System.setProperty("http.proxyPort", "80");
                System.setProperty("http.nonProxyHosts", "localhost|127.0.0.1");
                // settings proxy credentials
                System.setProperty("http.proxyUser", "xxxxxx");
                System.setProperty("http.proxyPassword", "xxxxxxxx");

                // HTTPS
                System.setProperty("https.proxyHost", "xxxxxxxxx");
                System.setProperty("https.proxyPort", "443");
                System.setProperty("https.proxyUser", "xxxxxxx");
                System.setProperty("https.proxyPassword", "xxxxxsxxx");


        final String username = "gmailuserid";
        final String password = "gmailpassword";

        Properties props = new Properties();
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "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("userid@gmail.com"));
            message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse("userid@gmail.com"));
            message.setSubject("test mail");

        //  otelInfo otelInfo = new otelInfo();
            String result2 = otel.otelInfo.readResults();
        //  System.out.println(result2);

            message.setText("Dear Mail Crawler,"+ result2);

            Transport.send(message);

            System.out.println("Done");

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

     }, 0, 1000 * 60 * MINUTES);

}}

以下是错误日志：

Exception in thread "Timer-0" java.lang.RuntimeException: com.sun.mail.util.MailConnectException: Couldn't connect to host, port: smtp.gmail.com, 587; timeout -1;
  nested exception is:
    java.net.ConnectException: Connection timed out: connect
    at otel.SendMailTLS$1.run(SendMailTLS.java:76)
    at java.util.TimerThread.mainLoop(Unknown Source)
    at java.util.TimerThread.run(Unknown Source)
Caused by: com.sun.mail.util.MailConnectException: Couldn't connect to host, port: smtp.gmail.com, 587; timeout -1;
  nested exception is:
    java.net.ConnectException: Connection timed out: connect
    at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2118)
    at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:712)
    at javax.mail.Service.connect(Service.java:388)
    at javax.mail.Service.connect(Service.java:246)
    at javax.mail.Service.connect(Service.java:195)
    at javax.mail.Transport.send0(Transport.java:254)
    at javax.mail.Transport.send(Transport.java:124)
    at otel.SendMailTLS$1.run(SendMailTLS.java:71)
    ... 2 more
Caused by: java.net.ConnectException: Connection timed out: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:331)
    at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:238)
    at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2084)
    ... 9 more