otp-reset.php

<?php
    require 'Assets/Mailer/PHPMailerAutoload.php';
    if(!isset($_SESSION))
    {   
        session_start();
    }
    if(isset($_SESSION['randomOTP']))
    {
        if(!isset($_GET['mailerror']) && !isset($_GET['otpsuccess']))
        {
            $mail = new PHPMailer;

            //$mail->SMTPDebug = 3;                               // Enable verbose debug output

            $mail->isSMTP();                                      // Set mailer to use SMTP
            $mail->Host = 'smtp.gmail.com';  // Specify main and backup SMTP servers
            $mail->SMTPAuth = true;                               // Enable SMTP authentication
            $sql = 'SELECT * FROM smtp';
            $result = mysqli_query($con,$sql);
            $row = mysqli_fetch_assoc($result);
            $mail->Username = "{$row['email']}";                 // SMTP username
            $mail->Password = "{$row['password']}";                           // SMTP password
            $mail->SMTPSecure = 'tls';                            // Enable TLS encryption, `ssl` also accepted
            $mail->Port = 587;                                    // TCP port to connect to

            $mail->setFrom("{$row['email']}", 'Charvi');
            $mail->addAddress("{$_SESSION['Remail']}", "{$_SESSION['Rname']}");     // Add a recipient
            $mail->addReplyTo('no-reply@gmail.com', 'Do Not Reply');

            $mail->isHTML(true);                                  // Set email format to HTML

            $mail->Subject = 'Verification OTP';
            $mail->Body    = "<h4>Your OTP For Verification is : <b>{$_SESSION['randomOTP']}</b></h4>";

            if(!$mail->send()) {
                $error='OTP could not be sent. Server Unreachable !';
                echo "<script>window.location.href='login.php?error={$error} & otperror=1 & mailerror=1';</script>";
            }
            else
            {
                $success="OTP is being send to {$_SESSION['Remail']}";
                echo "<script>window.location.href='login.php?success={$success}&otpsuccess=1';</script>";
            }
        }
?>

<section class="my-4">
    <div class="container col-md-6 col-sm-12 col-12">
        <h1 class="text-center">Enter OTP</h1>
        <form action="login.php" method="post" class="bg-light d-flex flex-wrap justify-content-center p-4 p-md-0 p-sm-0 need-validation">
            <div class="m-4 form-floating col-md-8 col-sm-12 col-11">
                <input type="number" class="form-control" id="otp" name="otp" placeholder="Enter The OTP" oninvalid="this.setCustomValidity('Please Enter Valid OTP')" oninput="this.setCustomValidity('')" required>
                <label for="otp">OTP</label>
            </div>
            <div class="col-md-12 col-sm-12 col-12 mb-4 d-flex justify-content-center gap-4">
                <button type="submit" class="btn btn-primary px-4" name="otpsubmit" id="otpsubmit" value="otpsubmit">Submit</button>
            </div>
        </form>
    </div>
</section>

<?php
    }
    else
    {
        echo "<script>window.location.href='login.php';</script>";
        
    }
?>