I've set up a Postfix installation based on http://flurdy.com/docs/postfix/ with modifications where I felt was sensible. Emails are being received fine until some users simply no longer receive emails from [big deals site].
- I've checked the settings for the user's subscription and they're not unsubscribed.
- I've signed up another user on my server for that deals site and they're coming through fine.
- I've got many users with this problem - 70 different newsletters simply stop coming through.
- I've sent email from my personal account to the users and it's coming through fine.
- In the mail logs I don't see any more connections from the deals site to that domain.
To me, it simply looks like the email provider just gives up trying to send to that user. Any ideas? Thanks.