form data not getting stored into mysql database

The data from the form is not getting stored in database for volunteer's registration. The same code for organization's registration is working. Please help.

<?php
    include("config.php");
    if(!$db){
        die("Connection Failed: ".mysqli_connect_error());
    }

    //Volunteer's Registration
    if(isset($_POST['volemail'],$_POST['volname'],$_POST['volbdate'],$_POST['volmob'],$_POST['volgen'],$_POST['voladdr'],$_POST['volorg'])){

        $volbdate=strtotime($_POST['volbdate']); 
        $volbdate=date("Y-m-d",$volbdate);

        //$rawdate = htmlentities($_POST['volbdate']);
        //$volbdate = date('Y-m-d', strtotime($rawdate));

        echo $volbdate;

        $sql1="insert into volunteer values('".$_POST['volemail']."','".$_POST['volname']."','$volbdate','".$_POST['volmob']."','".$_POST['volgen']."','".$_POST['voladdr']."','".$_POST['volorg']."')";


        if(mysqli_query($db,$sql1)){
            echo "Volunteer's registration Successful!";
        }

        else {
            echo "Error: " . $sql1 . "<br>" . mysqli_error($db);
        }
    }

?>