1. Create new policy group (for example: PolicyGroup_for_genuine_emails )
- Add mentioned genuine email address in members field
- On spam tab, turn off "Enable inbound spam and unwanted email scanning for this policy group"
4. Go to Spam Policy "Suspected Spam: Modify subject line with "[Suspected Spam]" (default)"
- Add new policy group, tick it, and save.
this solution will work. thanks karinjo