```
   <?php
    include "connection.php";

     if(!isset($_SESSION)) 
        { 
            session_start(); 
        } 
    $cand1  = $_POST['cand1'];

    $cand2  = $_POST['vice1'];

    $sess   =  $_SESSION['SESS_NAME'];

    if(!$cand1){
    $error="<center><h4><font color='#FF0000'>Please fill empty fields</h4></center></font>";
    include"student.php";
    exit();
    }

        $cand1 = addslashes($cand1);

        $cand1 = mysqli_real_escape_string($con,$cand1);

    $sql = 'SELECT * FROM student WHERE username="'.$_SESSION['SESS_NAME'].'" AND status="VOTED"';

    $result = mysqli_query($con,$sql);

                if (mysqli_num_rows($result)==1){

            $msg="<center><h4><font color='#FF0000'>You have already been voted, No need to vote again</h4></center></font>";
            include 'student.php';
            exit(); 
                }

                else{

                 $sql = 'UPDATE candidate SET votecount = votecount + 1 WHERE cand_id = "'.$_POST['cand1'].'" OR cand_id = "'.$_POST['vice1'].'"';

                $sql2 = 'UPDATE student SET status="VOTED" WHERE username="'.$_SESSION['SESS_NAME'].'"';

                $result = mysqli_query($con,$sql);
                $result2 = mysqli_query($con,$sql2);

        if(!$result && !$result2){
        die("Error on mysql query".mysqli_error());
        }
        else{
        $msg="<center><h4><font color='#FF0000'>Congratulation, you have made your vote.</h4></center></font>";
        include 'student.php';
        exit();
        }
                }

    ?>

```

the errors are at code including
 $sess= $\_SESSION['SESS\_NAME']; and at username="'.$\_SESSION['SESS\_NAME'].'"
i have tried every possibility so can you check my code?
mainly the error is undefined index at $session[session\_name]?