PHP mail() doesn't send e-mail - php

Question

I have a question for all you out there.
I've noticed that my php mail isn't sent anymore. So I looked into it to determine what the problem is but I can't seem to find it.
This is the case:
In powershell 3 (server 2012)I use the following command:
send-MailMessage -SmtpServer smtp.versatel.nl
and after giving the to e-mail address, a subject and a from address it sends the mail without any problem.
The code in the PHP file is:
INI_SET("SMTP", "smtp.versatel.nl");
$success = mail($to, $subject, $body, $header);
preg_match("/\d+/", $error["message"], $error);
if(!$success){$this->sFoutmelding ='Email is niet verstuurd.'.print_r($error);}
In the php.ini I disabled the default ini settings:
mail function]
; For Win32 only.
; SMTP = Smtp.versatel.nl
; smtp_port = 25
But still I get an error that the mail isn't sent:
Array ( )
Email is niet verstuurd.1
Why doesn't php send the mail when powershell does this perfectly?
Any ideas are welcome, I have searched on and off the whole week over the internet, but i can't find an answer.
*edit
I tried the var_dump and it gives, as expected, only a 'FALSE'.
Also the change in 'localhost' didn't do the trick. Still searching...

Answer 1

Its working, but still no explonation why :-) So if someone knows why, I like to know it too :-)
It still uses the same smtp server as without the phpmailer class. So the only thing I can think off is the fact that PHPmailer creates a different, more widly excepted, mail header than the default one of PHP.
I added the following code and class PHP mailer:
$success = $this->mail_attachment($to, $subject, $body);
protected function mail_attachment($mailto, $subject, $message) {
require_once("../PHPMailer/class.phpmailer.php");
//$file = $path.$filename;
$mail = new PHPMailer();
$mail->IsSMTP(); // telling the class to use SMTP
$mail->Host = "smtp.versatel.nl"; // SMTP server
$mail->From = "noreply#provider.foo";
$mail->FromName = "Sendername";
$mail->AddAddress($mailto);
$mail->Subject = $subject;
$mail->Body = $message;
$mail->WordWrap = 75;
//$mail->AddAttachment($file);
if(!$mail->Send()) {
echo 'Bevestigings e-mail is niet verzonden.';
echo 'Mailer error is: ' . $mail->ErrorInfo;
}
}