SMTP Error: Could not authenticate. while sending email in php - php

Question

Hi i am using PHPMailer for my website to send an email but getting error as SMTP Error: Could not authenticate.
This was error which i was getting.I have given the password correct and turned Allow less secure apps to "ON as well but still getting the same error.
020-01-25 09:11:24 SMTP ERROR: Password command failed: 534-5.7.14 <https://accounts.google.com/signin/continue?sarp=1&scc=1&plt=AKgnsbv534-5.7.14 oCoMr_x13f0BsQ-UMqe0zgPQOcVX9A7SY4fBk-WoLrRIJfT6uwspq7QpzlUjE8srm9esG534-5.7.14 73T38rlSCuGdkDRsjhkB3YQxKz3V8njuaclMAfqHskMAU3eX_1LYPH80oO9ZLkAl>534-5.7.14 Please log in via your web browser and then try again.534-5.7.14 Learn more at534 5.7.14 https://support.google.com/mail/answer/78754 i81sm528818ywe.82 - gsmtp
SMTP Error: Could not authenticate.
2020-01-25 09:11:24 CLIENT -> SERVER: QUIT
Here is the code which i have used for sending an email
<?php ob_start();
if(isset($_POST['submit_contact']))
{
require 'PHPMailer/PHPMailerAutoload.php';
$address = 'testing1#gmail.com';
$name=$_POST['name'];
$email =$_POST['email'];
$subject = $_POST['subject'];
$textMessage = $_POST['message'];
$mail = new PHPMailer();
$mail->IsSMTP();
$mail->SMTPDebug =1;
$mail->SMTPAuth = true;
$mail->SMTPSecure = 'tls';
$mail->Host = "smtp.gmail.com";
$mail->Port = 587;
$mail->CharSet = "UTF-8";
$mail->IsHTML(true);
$mail->Username = "testing#gmail.com";
$mail->Password = "PASSword1#3";
$message = array();
$message[] = 'Name : '.trim($name).' ';
$message[] = 'Email : '.trim($email).' ';
$message[] = 'Comment : '.trim($textMessage).' ';
$message = implode(',', $message);
$mail->SetFrom($email);
$mail->Subject = $subject;
$mail->Body = $message;
$mail->AddAddress($address);
if (!$mail->Send()) {
$msg = "Error while sending email";
$msgclass = 'bg-danger';
} else {
$msg = 'Thank you for contacting us.Will get back to you soon.....';
$msgclass = 'bg-success';
header("Location: contact.php");
}
}
?>
Here is the HTML Code which i have written
<form class="form-horizontal" action="contactus" method="post" role="form" enctype="multipart/form-data">
<?php if(isset( $msg)) {?>
<div class="<?php echo $msgclass; ?>" style="padding:5px;"><?php echo $msg; ?></div>
<?php } ?>
<div class="form-group">
<input type="text" name="name" id="name" class="form-control input-field" placeholder="Name" required="">
<input type="email" name="email" id="email" class="form-control input-field" placeholder="Email ID" required="">
<input type="text" name="subject" id="subject" class="form-control input-field" placeholder="Subject" required="">
</div>
<textarea name="message" id="message" class="textarea-field form-control" rows="4" placeholder="Enter your message" required=""></textarea>
<button type="submit" id="btnSend" value="Submit" class="btn center-block" name="submit_contact" >Send message</button>
<!-- Contact results -->
</form>

Answer 1

Always look at the information that’s right in front of you.
Read the troubleshooting guide linked from the error message - it tells you exactly how to deal with this precise problem — you most likely need to perform the “display captcha unlock” step.
It’s not just the “less secure apps” setting (which you can avoid by implementing XOAUTH2), it’s also that gmail imposes additional auth steps when logging in through a new mechanism (I.e. your script), which is briefly mentioned in the link they provide in the responses.