This is a test message generated from Cacti. This message was sent to test the configuration of your Mail Settings.
Try changing the sender email to the same one you used in the test email. It may be a mail server issue, rejecting the sender domain name.
Office 365 will definitely not allow you send as Localhost. You need to properly define the systems sender address.
May i know how to define?
i haven't config postfix ?
If you are going to hard code it, there's not point having any of the IF statements. But there is a setting where that should be defined under Configuration -> Settings -> Thresholds (I think it is - not in front of my cacti install right now).