Using Classic Outlook on Windows for personal email, calendar, and contact management
Hello MichalRama,
Thanks for your post in this community.
When a message is detected as automatically forwarded, and the outbound spam filter policy blocks that activity, this error occurs. To enable such forwarding settings, you need to make changes in your Anti-spam Outbound policy.
- For this, Login to Microsoft365 Defender > go to Policies & Rules > Threat Policies > select Anti-spam > (to directly go to Anti-spam policies page directly, login to https://security.microsoft.com/antispam > open your Anti-spam Outbound policy (default) > click on edit protection settings > Turn On Automatic forwarding rules option > save the changes.
- Screenshot for your reference:
To lean more about this, here sharing our official article, kindly see Configuring and controlling external email forwarding in Microsoft 365. - Office 365 | Microsoft Docs.
Thank you so much for your precious time. Stay safe and happy with good health.
Best Regards,
Ankita Vaidya