Issue with sending mails from a distribution mail id [Python]

Question

I have seen the following question but I still have a few doubts.

Sending an email from a distribution list

Firstly I have an individual mail account as well

Answer 1

reply: retcode (530); Msg: b'5.7.1 Client was not authenticated'

This means you need authentication. Outlook is likely using the same authentication for your existing account (since you only changed the From header).