Hello

To be clear : I'm no expert, doing my best.

I got in contact with the forum host but they say the server is not responsible for the malfunction. So I'm stuck between MLF that seems to have sent the mail (?) and the host that says it's not on their side (?).

To also be clear and to clarify how it's done: MLF itself sends no e-mail. MLF utilises the function mail to deliver the e-mail to the systems own mail transfer agent (MTA). That MTA, driven by your hosting company sends or sends not the e-mail. BUT it might be the case, that the MTA expects the mail-function of PHP to send special parameters with the e-mail during the delivery to the MTA.

As you said, there is an installation, that sends e-mails and one that don't. Please compare the advanced settings for the setting mail_parameter in both installations.

If MLF effectively sends the mail, how can I prove it to the Host ? Is there any log at MLF side that I can refer to or can this kind of logging be activated on demand?

No, there isn't and can't.

Here is the test code they gave to me. Seems to be the same as in functions.inc
I tried with \r\n instead of \n in my_mail in functions_inc but did not change anything.

<?php
$to = 'destinataire@domaine.tld';
$subject = 'un nouveau sujet';
$message = "Ceci essaie d'envoi d'email";
$headers = 'From: votreadresse@domaine.tld' . "\r\n" .
'Reply-To: votreadresse@domaine.tld' . "\r\n" .
'Return-Path:votreadresse@domaine.tld'."\r\n".
'X-Mailer: PHP/' . phpversion();

// Send
if(mail($to, $subject, $message, $headers)){
echo "ok";
}else{
echo"non envoyé";
}

Does the code sends an e-mail or not?

Tschö, Auge