Mail set up also resends out old emails
I have an Outlook.com account that was originally an msn.com account that I've just redirected to Mac Mail. The msn/outlook account is 11 years old.
When I hit "Get Mail" it is downloading all inbox emails from my server, which I expected. But it is also for some reason resending old emails, starting from 11 years ago. I stopped the process until I can figure out how to avoid this. The emails are not showing up in my Mac Mail sent folder. I'm not sure where they're coming from or how to stop them. I only know about it from two people who received these old emails from me.
Can anyone explain this and how to avoid it in setting up Mac Mail?