How to solve caused by: java.net.sockettimeoutexception: read timed out

i am getting this error.This error occurs when I send the confirmation code to the email of the registered user, but either succeeds or fails.

    javax.mail.MessagingException: Exception reading response;
      nested exception is:
        java.net.SocketTimeoutException: Read timed out
        at com.sun.mail.smtp.SMTPTransport.readServerResponse(SMTPTransport.java:2445)
        at com.sun.mail.smtp.SMTPTransport.ehlo(SMTPTransport.java:1684)
        at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:730)
        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 az.unibank.employee.mail.SendEmail.send(SendEmail.java:49)
        at az.unibank.employee.mail.SendEmail.lambda$sendAsync$0(SendEmail.java:13)
        at java.lang.Thread.run(Thread.java:748)
    Caused by: java.net.SocketTimeoutException: Read timed out
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
        at java.net.SocketInputStream.read(SocketInputStream.java:171)
        at java.net.SocketInputStream.read(SocketInputStream.java:141)
        at com.sun.mail.util.TraceInputStream.read(TraceInputStream.java:126)
        at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
        at java.io.BufferedInputStream.read(BufferedInputStream.java:265)
        at com.sun.mail.util.LineInputStream.readLine(LineInputStream.java:104)
        at com.sun.mail.smtp.SMTPTransport.readServerResponse(SMTPTransport.java:2425)
        ... 10 more

public class SendEmail {

    public static void sendAsync(String toEmail, String text, String subject) {

        new Thread(() -> {
            send(toEmail, text, subject);
        }).start();

    }

    public static void send(String toEmail, String text, String subject) {

        final String username = "anar.memmedov1501@gmail.com";
        final String password = "sAlam12345";

        Properties prop = new Properties();
        prop.put("mail.smtp.host", "smtp.gmail.com");
        prop.put("mail.smtp.port", "587");
        prop.put("mail.smtp.auth", "true");
        prop.put("mail.smtp.starttls.enable", "true");
        Session session = Session.getInstance(prop,
                new javax.mail.Authenticator() {
            @Override
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });

        try {

            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress(username));
            message.setRecipients(
                    Message.RecipientType.TO,
                    InternetAddress.parse(toEmail)
            );
            message.setSubject(subject);
            message.setText(text);

            Transport.send(message);

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

}

and this my send email code this problem occurs occasionally, but it wasn't like this before. I can't quite understand why. is there anyone,who help me?

I seriously can't handle this problem, I don't understand why.