How to not tag "newsletter" (mail from our domain) Fortimail

Hi
an email sent from sender@our_domain to  mailinglist@our_domain using the protected mail server never goes out from mail server; it is delivered locally
Do you are sending it from external mail server and you want also avoid antispoofing blocks?
SPF/DKIM/DMARC records in order to validate all sources authorized to send @our_domain  for.
And adjust IP policies eventually if you need control IP origin.