What about when the mail server endpoint has changed, and for whatever reason, this configuration wasn’t updated? This is a common scenario when dealing with legacy infrastructure in my experience.
What about when the mail server endpoint has changed, and for whatever reason, this configuration wasn’t updated? This is a common scenario when dealing with legacy infrastructure in my experience.
the whole point of the essay here is that you should make a distinction between errors that you care about and plan to fix, and errors that you don't care about and don't intend to do anything about. and if you don't intend to do anything about it, it shouldn't be logged as error.
i'm following the author's example that an SMTP connection error is something you want to investigate and fix. if you have a different system with different assumptions where your response to a mailserver being unreachable is to ignore it, obviously that example doesn't apply for you. i'm not saying, and i don't think the author is saying that SMTP errors should always or never be logged as errors.
when the mailserver endpoint has changed, you should do the thing that makes sense in the context of your application. if it's not something that the person responsible for reviewing the logs needs to know about, don't log it. if it is, then log it.