Bagaimana mengatasi base64 yang gagal decode di imap php?

Bagaimana mengatasi content email yang gagal decode di imap php?

Beberapa berhasil decode, tapi beberapa ada yang gagal.

Berikut potongan program yang saya buat :

//controller
$conn                  = imap_open($host, $user, $password);
if (!$conn) {
     $v['connInfo']    = '<strong>Unable to connect : </strong> '.imap_last_error();
     imap_close($conn);
} else {
     $v['connInfo']    = '';
     $header           = imap_headerinfo($conn, $email_id);
     $overview         = imap_fetch_overview($conn, $email_id, 0);
     $structure        = imap_fetchstructure($conn, $email_id);
     $message          = imap_fetchbody($conn, $email_id, 1);
     $message          = imap_binary($message);

     if(isset($structure->parts) && is_array($structure->parts) && isset($structure->parts[1])) {
          $part        = $structure->parts[1];
          print_r($part->encoding);
          switch ($part->encoding) {
               # 7BIT
               case 0: $message = imap_qprint($message);
               # 8BIT
               case 1: $message = quoted_printable_decode(imap_8bit($message));
               # BINARY
               case 2: $message = imap_binary($message);
               # BASE64
               case 3: $message = imap_base64($message); //$message = base64_decode($message);
               # QUOTED-PRINTABLE
               case 4: $message = quoted_printable_decode($message);
               # OTHER
               case 5: $message = $message;
               # UNKNOWN
               default: $message = $message;
          }
     }
     $v['message']           = $message;
     imap_close($conn);
}

//view
<div class="panel-body">
     <?php
          if (base64_decode($message, true)) {
               $message = base64_decode($message);
               echo nl2br($message);
          } else {
               echo nl2br($message);
          }
      ?>
</div>

Contoh content email yang gagal decode :

1. Contoh 1

imap01.PNG

2. Contoh 2

imap02.PNG

3. Contoh 3

imap03.PNG

Ketiga contoh email tersebut berasal dari email yang berbeda.

Terimakasih