Why i am unable to insert values into database?

I am using the below code to insert data into database but its not working. I am using procedural way to insert data into MySQL DB with the help of PHP.

    <?php 


$conn = mysqli_connect("localhost", "root", "", "smartemployer");
// Check connection
if($conn === false){
   die("ERROR: Could not connect. " . mysqli_connect_error());
}
else{echo"Connection built<br>";}

$OrganizationID =  1254;
$FirstName =  $_POST['fname'];
$LastName =  $_POST['lname'];
$Email =  $_POST['email'];
$Country=  $_POST['country'];
$City=  $_POST['city'];
$Industry=  $_POST['industry'];
$CompanySize=  $_POST['companySize'];
$CompanyWeb=  $_POST['companywebsite'];
$Password=  $_POST['password'];

$sql = "INSERT INTO employers (OrganizationID,FirstName,LastName,Email,Country,City,Industry,CompanySize,CompanyWeb,AccountPassword) 
VALUES('".$OrganizationID."','".$FirstName."','".$LastName."','".$Email."','".$Country."','".$City."','".$Industry."','".$CompanySize."','".$CompanyWeb."','".$Password."')"; 

if (mysqli_query($conn, $sql))
{ 
   header('Location: Response.html');
}
   else 
   { echo "Error: "; 
   }

  // Close connection
mysqli_close($conn); 
?>