dompdf is showing utf-8 language all words (?) question mark

Question

i am using dompdf with laravel 5.6 and when i export my pdf it shows all the charachters of that language in a question mark formart like this

????????????????

i read to give it font DejaVu to be fixed but that didnt worked out here is my code

    <h1 class="test">مثال(something in persian language)</h1>

and css of

.test {
        font-family: 'DejaVuSans';
        font-size: 25px;
    }

and controller

 public function downloadPDF($id){
    $invoices = invoices::find($id);

    $pdf = PDF::loadView('admin.invoices.pdf', compact('invoices'));
    return $pdf->download('invoice.pdf');

}