Have you tried the "Exchange Mail Flow Troubleshooter" in Exchange Troubleshooting Assistant v1.0 (ExTRA)? This is a new troubleshooter that you can use to troubleshoot common mail flow problems ...
Updated Aug 26, 2026
Version 3.0
Blog Post
5 MIN READ
Mail Flow Troubleshooter in Exchange Troubleshooting Assistant (ExTRA) - A closer look
When I forward mail to another user by way of the Forwarding address, Forward to: options in the Delivery Options dialog, the IMF filter seems to not work. The mailbox threshold is ignored and all messages are delivered regardless of thier SLC rating. Any ideas why or how to prevent this?