php form doesn't send [closed]

Question

When I submit my form it Dies for an unkown reason.

My form code:

    <form action="mail.php" method="post">
        <input class="invoeren" name="naamUser" type="text" placeholder="Naam" required>
        <input class="invoeren" name="nummerUser"  type="text" placeholder="Telefoonnummer" required>
        <input class="invoeren" name="onderwerpUser"  type="text" placeholder="Onderwerp" required>
        <textarea class="invoeren" type="text" name="opmerkingUser"  placeholder="Opmerking" required></textarea>           
        <button type="submit" id="contactButton">Verstuur</button>
    </form>

My mail.php file:

<?php 
    ob_start(); 

    $naamUser = $_POST['naamUser'];
    $nummerUser = $_POST['nummerUser'];
    $onderwerpUser = $_POST['onderwerpUser'];
    $opmerkingUser = $_POST['opmerkingUser'];


    $formcontent="Aanvraag formulier Domein naam \n
    Naam: $naamUser \n
    Telefoonnummer: $nummerUser \n
    Onderwerp: $onderwerpUser \n
    Opmerking: $opmerkingUser \n              
                  ";              

    $recipient = "[email protected]";

    $subject = "Terug Bellen";

    $mailheader = "From: $naamUser \r\n";

    mail($recipient, $subject, $formcontent, $mailheader) or die("Error!");
    ?>

I use 1 mail.php file for several index.html files, is that maybe the reason why it dies?

Answer 1

"Can you answer this question by your comment? @Fred-ii- Because that's the answer, thanks! – Blank"

As per OP's request:

From: expects an email address, not a name.

• Check your spam.

Read the manual on mail()

• http://php.net/manual/en/function.mail.php

and another comment:

Add error reporting to the top of your file(s) right after your opening PHP tag for example

<?php error_reporting(E_ALL); ini_set('display_errors', 1); then the rest of your code, to see if it yields anything and make sure you've access to mail() and that PHP is in fact running properly.