title: PHP mail() function does not send e-mails
body: <p>I have a simple form, where users enter their e-mail address. They should receive a message afterwards via this code:</p>
  
  <pre><code>$name = mysqli_real_escape_string($con, $_POST['jmeno']);
  $surname = mysqli_real_escape_string($con, $_POST['prijmeni']);
  $email = mysqli_real_escape_string($con, $_POST['email']);
  $subject = "Subject";
  $message = "Message text";
  
  $sql="INSERT INTO kucharka (jmeno, prijmeni, email)
  VALUES ('$name', '$surname', '$email ')";
  
  mail($email,$subject,$message,"From: my@address.cz\n");
  </code></pre>
  
  <p>If I switch the to address to a fixed e-mail, it works properly. Could you please point mw towards a solution? I can't see a mistake there.</p>
  
  <p>Kindly thank you.</p>