navbar toggle görünmüyor mobilde

arkadaşlar acilk yardımcı olurmusunuz navbar toggle yani mobil menü görünmüyor masaüstünde sıkıntı yok dropdownlarda çalışıyor

<nav class="navbar navbar-expand-lg navbar-dark bg-primary">
  <a class="navbar-brand" href="[URL="http://localhost/wm/index.php#"]#[/URL]"><img src="[URL="http://localhost/wm/image/logo.png"]image/logo.png[/URL]" </a>
    <button class="navbar-toggle" data-target=".navbar-ex1-collapse" data-toggle="collapse" type="button"><span class="sr-only">Toggle navigation</span> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span></button>
    <span class="navbar-toggler-icon"></span>
  <div class="collapse navbar-collapse" id="main_nav">
<ul class="navbar-nav pull-right">
    <li class="nav-item active"> <a class="nav-link" href="[URL="http://localhost/wm/index.php#"]#[/URL]">ANASAYFA </a> </li>
    <li class="nav-item"><a class="nav-link" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> HAKKIMIZDA </a></li>
   
    <li class="nav-item dropdown">
       <a class="nav-link  dropdown-toggle" href="[URL="http://localhost/wm/index.php#"]#[/URL]" data-toggle="dropdown">  GÜÇ KALİTESİ  </a>
        <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Reaktif Güç</a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Harmonikler </a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Rezonans </a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Transient </a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Şebeke Kirliliği </a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Haberleşme Hataları </a></li>
        </ul>
    </li>
   
        <li class="nav-item dropdown">
       <a class="nav-link  dropdown-toggle" href="[URL="http://localhost/wm/index.php#"]#[/URL]" data-toggle="dropdown">ÇÖZÜMLER </a>
        <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Reaktif Güç</a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Kontaktörlü</a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Tristörlü</a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> IGBT Tabanlı</a></li>
        </ul>
    </li>
   
        <li class="nav-item dropdown">
       <a class="nav-link  dropdown-toggle" href="[URL="http://localhost/wm/index.php#"]#[/URL]" data-toggle="dropdown">HARMONİKLER</a>
        <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Akım Harmoniği</a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Gerilim Harmoniği</a></li>
        </ul>
    </li>
   
<li class="nav-item dropdown">
       <a class="nav-link  dropdown-toggle" href="[URL="http://localhost/wm/index.php#"]#[/URL]" data-toggle="dropdown">REZONANS</a>
        <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> P200</a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]">RESI</a></li>
        </ul>
    </li>
   
   
<li class="nav-item dropdown">
       <a class="nav-link  dropdown-toggle" href="[URL="http://localhost/wm/index.php#"]#[/URL]" data-toggle="dropdown">TRANSIENT</a>
        <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> RC Filtre</a></li>
        </ul>
    </li>
   
<li class="nav-item dropdown">
       <a class="nav-link  dropdown-toggle" href="[URL="http://localhost/wm/index.php#"]#[/URL]" data-toggle="dropdown">ŞEBEKE KİRLİLİĞİ</a>
        <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Sensorless Control</a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Sofia</a></li>
        </ul>
    </li>
   
<li class="nav-item dropdown">
       <a class="nav-link  dropdown-toggle" href="[URL="http://localhost/wm/index.php#"]#[/URL]" data-toggle="dropdown">HABERLEŞME HATALARI</a>
        <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> EMC Analizi</a></li>
        </ul>
    </li>
    <li class="nav-item"><a class="nav-link" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> ANALİZ </a></li>
<li class="nav-item dropdown">
       <a class="nav-link  dropdown-toggle" href="[URL="http://localhost/wm/index.php#"]#[/URL]" data-toggle="dropdown">WOMNER AKADEMİ</a>
        <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Reaktör Kondansatör Eşleştirmesi</a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Harmonikler Hakkında</a></li>
            <li><a class="dropdown-item" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> Kondansatör Gerilim Hesabı</a></li>
        </ul>
    </li>
     <li class="nav-item"><a class="nav-link" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> PARTNERLER </a></li>
     <li class="nav-item"><a class="nav-link" href="[URL="http://localhost/wm/index.php#"]#[/URL]"> İLETİŞİM </a></li>
   
   
   
</ul>
  </div> <!-- navbar-collapse.// -->
</nav>

bu şekilde kimse bişey anlayamaz. Ögeyi denetle yaparak navbarın mobil versiyonda aldığı css kuralına bakın. Arada bootstrap ekran boyutuna göre gizlebiliyor.