contactmail versturen mbv phpMailer

<?php
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

	use PHPMailer\PHPMailer\PHPMailer;
	use PHPMailer\PHPMailer\Exception;

	require 'PHPMailer/src/Exception.php';
	require 'PHPMailer/src/PHPMailer.php';
	require 'PHPMailer/src/SMTP.php';
	
	//Set variables
	$firstname = $lastname = $email = $contactmessage = "";
	$err = array();
	$msg = "";
	
	//Make function to test the input data
	function test_input($data) {
		$data = trim($data);
		$data = stripslashes($data);
		$data = htmlspecialchars($data);
		return $data;
	}
	
	if ($_SERVER['REQUEST_METHOD'] == 'POST') {
		if (empty($_POST['firstname'])) {
			$err['firstname'] = "Firstname is required";
			//Limit length and strip HTML tags
		} else {
			$firstname = test_input($_POST['firstname']);
			if(!preg_match("/^[a-zA-Z ]*$/",$firstname)) {
				$err['firstname'] = 'Only letters and white space allowed!';
			}
		}
		if (empty($_POST['lastname'])) {
			$err['lastname'] = "Lastname is required";
			//Limit length and strip HTML tags
		} else {
			$lastname = test_input($_POST['lastname']);
			if(!preg_match("/^[a-zA-Z ]*$/",$lastname)) {
				$err['lastname'] = 'Only letters and white space allowed!';
			}
		}
		//Make sure the address they provided is valid before trying to use it
		if (empty($_POST['email'])) {
			$err['email'] = 'Email is required';
		} else {
			$email = test_input($_POST['email']);
			if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
			  $err['email'] = "Invalid email format"; 
			}
		}
		//Apply some basic validation and filtering to the message
		if (empty($_POST['contactmessage'])) {
			$err['contactmessage'] = 'What is your message';
			//Limit length and strip HTML tags
		} else {
			$contactmessage = test_input($_POST['contactmessage']);
		}
		$name = $firstname.' '.$lastname;
		if (count($err) == 0)  {
			require_once '../../data/data.php';
			$mail = new PHPMailer;
			$mail->isSMTP();
			$mail->SMTPDebug = 4;
			$mail->Host = $host;
			$mail->Port = $port;
			$mail->SMTPSecure = 'ssl';
			$mail->SMTPAuth = true;
			$mail->Username = $user;
			$mail->Password = $pass;
				//It's important not to use the submitter's address as the from address as it's forgery,
				//which will cause your messages to fail SPF checks.
				//Use an address in your own domain as the from address, put the submitter's address in a reply-to
			$mail->setFrom = ($from.', '.$fromName);
			$mail->addReplyTo($email, $name);
			$mail->addAddress = ($addAddress.', '.$addName);
			$mail->Subject = 'Contact request';
			$body = 'Name: '.$firstname.' '.$lastname;
				$body .= '<br>Email: '.$email;
				$body .= '<br>Message: '.$contactmessage;
			$mail->Body = $body;
			$mail->AltBody = $body;
				
			//include_once '../../data/data.php';
			if ($mail->send()) {
				$success = "<p style='margin-left:10%;padding-bottom:2%;width:60%'><strong>Thank you for contacting us.<br>The following message is successfully sent:</strong><br>";
				$success .= $name."<br>".$email."<br>".$contactmessage."</p>"; 
				
			}		
			else {
				$fail= 'Mailer Error: ' . $mail->ErrorInfo;
			}
		}
	}
?>