PHP未发送电子邮件，提交按钮将我发送到空白页

Question

“提交”按钮将我发送到一个空白页面，我在那里获得mysite.com/mail.php，我不在本地主机上，所以一切都在站点上，所以我不确定为什么我继续看到php按下提交按钮时，下面的代码。这是我第一次使用php，并且还将网站上传到虚拟主机。任何帮助将不胜感激。

<!-- Form -->
                    <section>
                        <header class="major">
                            <h2>Request a Free onsite Consultation</h2>
                        </header>
                        <div class="row">
                            <div class="col-6 col-12-small">
                                <section class="box">
                                    <form method="post" action="mail.php" >
                                        <div class="row gtr-50 ">

                                            <div class="col-5 col-12-small ">
                                                <input name="name" placeholder="First and Last Name" type="text" />
                                            </div>

                                            <div class="col-5 col-12-small">
                                                <input name="phone" placeholder="Phone Number" type="text" />
                                            </div>
                                            <div class="col-5 col-12-small">
                                                <input name="email" placeholder="Email" type="text" />
                                            </div>
                                            <div class="col-5 col-12-small">
                                                <input name="city" placeholder="City" type="text" />
                                            </div>
                                            <div class="col-12">
                                                <textarea name="message"
                                                    placeholder="Let us know what you're looking to get."></textarea>
                                            </div>
                                            <div class="col-12">
                                                    <button class=" icon solid fa-envelope" 
                                                     type="submit" >Send Message</button>
                                                
                                            </div>
                                        </div>
                                    </form>

                                </section>

**My php code for how to handle the users info**

  <?php
 $myemail = "myemail@emailprovider.com";
 $errors ="";



 if(isset($_POST['submit'])){

 $name = $_POST['name']; 
 $phone = $_POST['phone'];
 $email_address = $_POST['email']; 
 $city = $_POST['city'];  
 $message = $_POST['message']; 

 if(empty($_POST['name'])  || {
 empty($_POST['email']) ||
 empty($_POST['phone']) ||  
 empty($_POST['city'])  || 
empty($_POST['message']))
{
 $errors .= "\n Error: all fields are required";
  }
 }



  $to = $myemail;

  $email_body = "You have received a new message from:  $name \n ".

   "From City: $city \n".

   "Phone Number: - $phone \n".

   "Their Email is: $email_address\n  and Message:  \n $message";


   $headers = "Reply-To: $email_address";

    mail($to,$email_body, $headers);



    echo"Location:  thankyou.html";

   }

    ?>