PHP Mysqli Error Input Data

Kode Ane

<?php

  include '../lib/config.php';

  $user   = $_POST['username'];
  $pass   = md5($_POST['password']);
  $nama   = $_POST['nama'];
  $jbtn   = $_POST['jabatan'];
  $gbr    = $_POST['gambar'];

  if ($_POST['tambah']) {
    $tambah = mysqli_query($conn, "INSERT INTO admin VALUES ('','$user','$pass','$nama','$jbtn','$gbr')");

    if ($tambah) {
      echo "<script>alert('Moderator Ditambahkan!'); window.location = 'index.php'</script>";
    } else {
      die ('Gagal!' .mysqli_error($conn));
    }
  }

?>

Ane input data dari form, length gak ada yang lebih, dan ane baru liat Error php mysqli ini

You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'dimas','e4c44b92413565264651f5d4ad60ecba','DimasPur','Moderator','src/moderator.' at line 1

Tolong Jawabannya :)