This is the first time I’m using PHPMailer and I’m getting error 500 when I send a message through the form on my website.

I also tried port number 587 but I get the same error.
Probably I’ve set something wrong in the server configuration.

What username and password should I put? The credentials of the Microsoft account or just the email and password of the address you want to send emails with?
At this point I am a bit confused.

Also regarding the tls. The person who set up the environment and sent me the credentials, told me to only use TLS version 1.2. Is this something that I can set on the code or that can cause the error 500?

$mail = new PHPMailer(true);

try {
    // server configuration
    $mail->isSMTP();
    $mail->Host       = 'smtp.office365.com'; // host server smtp
    $mail->SMTPAuth   = true;
    $mail->Username   = '[email protected]'; // what username? the email address?
    $mail->Password   = 'password'; // smtp pss
    $mail->SMTPSecure = 'tls';
    $mail->Port       = 25; // tcp port for smtp

    // recipients
    $mail->setFrom('[email protected]', 'Company Name'); // should this be the same as the username?
    $mail->addAddress('[email protected]', 'Mary'); is this and extra email address where I want receive the data
    $mail->addAddress('[email protected]', 'Jhon');

    // email contents
    $mail->isHTML(true); // html email format
    $mail->Subject = 'New message from $name';
    $mail->Body    = $message;
    $mail->AltBody = 'This is the body in plain text for non-HTML mail clients';

    $mail->send();
    echo 'Message has been sent';
} catch (Exception $e) {
    echo "Message could not be sent. Mailer Error: {$mail->ErrorInfo}";
}