When Mailster sends an email via your chosen delivery method it always relies on the response of your sending server. Sometimes the message has been sent but not actually delivered.
Sendmail is a mail transfer client which is used on many providers Make sure the the path “/usr/sbin/sendmail” is correct Make sure you have the permission to send with sendmail (ask provider for help). Shared hosts often disabled this function. Try a different sending method at Settings => Newsletter => Delivery Sendmail isn’t designed for […]