Ghost was installed on this host in early 2016. Using resources like this: https://www.ghostforbeginners.com/example-config-js-sendmail/
This config then refused to start. Great kudos that the error message is nice and clear.
I removed the offending line - after:
I note that the email From: for Ghost 3.0 has changed, formerly ghost@… and now noreply@… - which caused my initial email tests from the upgraded blog to fail. Once I had updated permissions to allow local sending from the new address, the SMTP transport works.
The release notes for Ghost 3.0.0 seem very lacking - I wonder what other aspects of config.production.json are no longer optimal or relevant? A Note on a recommended vanilla config for the new version would make sense too. Perhaps I should be using transport ‘Direct’??