Short answer:
If emails sent from Microsoft Teams or Planner are undeliverable after enabling Xink server-side, update the Xink mail flow rule to exclude these messages based on a specific message header.
Why this happens
After enabling Microsoft 365 server-side, emails sent from Microsoft Teams or Planner may fail to deliver.
This occurs because these services use special message headers that can conflict with the Xink rerouting rule.
Solution: Add exclusion to the Xink rule
To resolve the issue, update the Xink-Auto-Rerouting-Catcher rule in the Exchange Admin Center.
Step-by-step
- Go to Exchange Admin Center > Mail flow > Rules.
- Select Xink-Auto-Rerouting-Catcher and click Edit.
- Add a condition:
- A message header
- Includes any of these words
Header name:
X-MS-Exchange-UnifiedGroup-SubmittedViaGroupAddress
Words or phrases:
/o=ExchangeLabs/ou=Exchange Administrative Group
- Click Save.
Result
Emails sent from Microsoft Teams and Planner will bypass the Xink rerouting rule and be delivered successfully.
