Contact Form' da nerde yanlış yapıyorum?

<div class="col-lg-8">
<form class="form-contact contact_form" action="contact_process.php" method="post" id="contactForm"
novalidate="novalidate">
<div class="row">
<div class="col-12">
<div class="form-group">

<textarea class="form-control w-100" name="message" id="message" cols="30" rows="9"
onfocus="this.placeholder = ''" onblur="this.placeholder = 'Enter Message'"
placeholder='Mesajı Gönder'></textarea>
</div>
</div>
<div class="col-sm-6">
<div class="form-group">
<input class="form-control" name="name" id="name" type="text" onfocus="this.placeholder = ''"
onblur="this.placeholder = 'Adınız'" placeholder='Enter your name'>
</div>
</div>
<div class="col-sm-6">
<div class="form-group">
<input class="form-control" name="email" id="email" type="email" onfocus="this.placeholder = ''"
onblur="this.placeholder = 'Mail Adresiniz'" placeholder='Enter email address'>
</div>
</div>
<div class="col-12">
<div class="form-group">
<input class="form-control" name="subject" id="subject" type="text" onfocus="this.placeholder = ''"
onblur="this.placeholder = 'Konu'" placeholder='Enter Subject'>
</div>
</div>
</div>
<div class="form-group mt-3">
<button type="submit" class="button button-contactForm btn_1">Mesajı Gönder <i class="flaticon-right-arrow"></i> </button>
</div>
</form>
</div>