Could not convert socket to tls javax.mail.messagingexception

A JavaMail error!

The error "Could not convert socket to TLS" is typically caused by a problem with the SSL/TLS handshake between your Java application and the mail server. Here are some possible solutions:

Check the mail server's SSL/TLS configuration: Ensure that the mail server is configured to use SSL/TLS and that the certificate is valid. You can use tools like OpenSSL to test the certificate.
Verify the JavaMail version: Make sure you're using a recent version of JavaMail. Older versions may not support TLS 1.2 or later, which is the default protocol used by many mail servers.

Specify the TLS protocol: Try specifying the TLS protocol version in your JavaMail code. For example:

Properties props = new Properties();
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.starttls.required", "true");
props.put("mail.smtp.ssl.protocols", "TLSv1.2");

Check the Java version: Ensure that your Java version is compatible with the mail server's SSL/TLS configuration. Java 8 and later versions support TLS 1.2 and later.
Disable SSL/TLS verification: If you're using a self-signed certificate or a certificate that's not trusted by the Java runtime, you can disable SSL/TLS verification:
```
props.put("mail.smtp.ssl.trust", "*");
```
However, this is not recommended as it can lead to security vulnerabilities.
Check the mail server's hostname: Ensure that the hostname used in your JavaMail code matches the hostname in the mail server's certificate.
Check the JavaMail configuration: Verify that your JavaMail configuration is correct, including the mail server's hostname, port, and authentication settings.

Here's an example of a JavaMail configuration that uses TLS:

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

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

Transport transport = session.getTransport();
transport.connect();

If none of these solutions work, please provide more details about your JavaMail code, the mail server you're using, and the error message you're seeing.

Mail Knowledge

Could not convert socket to tls javax.mail.messagingexception