Couldn't connect to host port mail.gmail.com 25 timeout gmail java

A Java-related issue!

The error message "couldn't connect to host port mail.gmail.com 25 timeout" suggests that your Java application is trying to connect to Gmail's SMTP server (mail.gmail.com) on port 25, but the connection is timing out.

Here are a few possible reasons and solutions:

1. Gmail's SMTP server block: Gmail has strict security measures in place to prevent spam and abuse. By default, Gmail blocks connections from applications that don't use OAuth 2.0 or have a valid SMTP relay. You can try enabling "Less secure app access" in your Google Account settings to allow your Java application to connect to Gmail's SMTP server. However, this is not recommended as it compromises your account security.
2. Firewall or network issues: Check if there are any firewall rules or network issues that might be blocking the connection. Ensure that your Java application has the necessary permissions to connect to the internet.
3. Java Mail API configuration: Verify that your Java Mail API configuration is correct. Make sure you're using the correct SMTP server, port, and authentication details. You can try setting the mail.smtp.starttls.enable property to true to enable TLS encryption.
4. Timeout issues: The timeout error might be due to a connection timeout or a read timeout. You can try increasing the timeout values in your Java Mail API configuration. For example, you can set the mail.smtp.connectiontimeout property to a higher value (e.g., 30 seconds).
5. Java Mail API version: Ensure that you're using a compatible version of the Java Mail API. You can try updating to the latest version or using a different Java Mail API implementation.

Here's an example of how you can configure the Java Mail API to connect to Gmail's SMTP server:

import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class GmailSMTP {
    public static void main(String[] args) {
        Properties props = new Properties();
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.port", 587);
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.timeout", 30000); // 30 seconds

        Session session = Session.getInstance(props, new Authenticator() {
            @Override
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication("your-gmail-username", "your-gmail-password");
            }
        });

        try {
            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("[email protected]"));
            message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("[email protected]"));
            message.setSubject("Test email");
            message.setText("Hello, this is a test email.");

            Transport.send(message);
            System.out.println("Email sent successfully!");
        } catch (MessagingException e) {
            System.out.println("Error sending email: " + e.getMessage());
        }
    }
}

Remember to replace the placeholders (your-gmail-username, your-gmail-password, and recipient-email) with your actual Gmail credentials and the recipient's email address.