[AndreT]

There's a lot of room for error if it has reached the PHP execution.

What you could do is see what the mail function returns.

PHP код:

$isSent = mail(...);
if($isSent)
    echo 'Mail was accepted for delivery!';
else
    echo 'Mail was not accepted for delivery!'; 


If it was accepted for delivery, then as the PHP manual says, the mail still might not reach its destination. There are a lot of things that could be wrong: PHP mailserver settings, it could get stuck in spam filters, etc.

Quote:

Returns TRUE if the mail was successfully accepted for delivery, FALSE otherwise. It is important to note that just because the mail was accepted for delivery, it does NOT mean the mail will actually reach the intended destination.