In an effort to prevent spam I am trying to remove fake or bad e-mails from our database. One of the ways I want to do this is to check the maillog and if an e-mail is not sent then the recipient is removed from the database.
So if the status=Bounced this is fine but what about status=Deferred? The vast majority of the bad e-mails get the Deferred status. It would be far easier to delete these to but I am not sure if this status could end up deleting good e-mails?
I'd also like to stop postfix trying to re-send deferred e-mails, again I don't know if this will mean legitimate e-mails will not get sent.
I have searched around and can't find a good definition of this status and whether it is likely that a deferred e-mail will end up getting sent a second time.
Best Answer
In case of Yahoo, if you are getting this error
It means, you are sending more emails than your IP and Sending domain reputation allows. Yahoo allows only 100 mails/day approx for a new IP address before giving that error TSS04, The number might change based on your content and sending domain. Its better to warm up your IP slowly and build your reputation.
This thread might be useful to you, https://serverfault.com/a/1016122/549576