Get already exists error when trying to set anti spam policy

The error indicates that a hosted outbound spam policy (rule) named COUSBC forwarding already exists in the service, even though it is not visible in the UI. To resolve this, use Exchange Online PowerShell to locate and, if needed, remove or rename the existing object.

1. Connect to Exchange Online PowerShell Use the steps in Connect to Exchange Online PowerShell (referenced in the context) to establish a session.
2. List existing spam filter rules Run:

      Get-HostedContentFilterRule -State Enabled
   

   Review the output for a rule with a name matching or similar to COUSBC forwarding. If needed, run:

      Get-HostedContentFilterRule | Format-Table Name, Priority, SentTo, SentToMemberOf, RecipientDomainIs
   

   to see all enabled rules and identify the one that conflicts.
3. Remove the conflicting rule (if appropriate) If COUSBC forwarding (or the conflicting rule) is found and should no longer exist, remove it with:

      Remove-HostedContentFilterRule -Identity "COUSBC forwarding"
   

   or, if the actual name differs, substitute the exact rule name from the Get-HostedContentFilterRule output.
4. Recreate or adjust the outbound spam/forwarding configuration After the conflicting rule is removed, recreate the outbound spam policy or forwarding configuration as needed. For outbound spam policies in the Microsoft Defender portal:
   • Go to https://security.microsoft.com → Email & collaboration → Policies & rules → Threat policies → Anti-spam.
   • Use Create policy → Outbound to configure a new outbound spam policy and scope it to the required users, groups, or domains.

If the rule must remain but only its settings need to change, use Set-HostedContentFilterPolicy (for the policy) and adjust its associated rule instead of creating a new one with the same name.

References:

• Configure anti-spam policies for cloud mailboxes
• Configure outbound spam policies for cloud mailboxes
• Troubleshoot common anti-spam policy issues