Our web site (Apache/Unix) generates orders (200-400 a day) which are sent both to customers an processing center. To do this, I use PhpMailer (Mail).
Usually, Send() returns true, but ~1-2% of mails don't reach their destinations (either customer or processing center or both).
It also could happen a period (usually on a weekend, for example - this Sunday between 5pm-7pm ) when Send() returns false in 30-50% of mailes, even if I retry it few times.
In order to decrease the number of filed emails, I send the order to 2 independent destinations, but it did not help much - during this strange period where ~30% of emails failed, only 5% of them were delivered to an alternative address.
My general question is too general - how can I improve the situation with emails?
are there more reliable, supported classes for php mail?
is there a way to check PhpMailer and system logs to find out what was sent, what was not and why?