Fix OOF Autoreply Issues with Xink Server-Side

Short answer:
Autoreply (Out of Office) messages may not be delivered when Xink server-side is enabled because Microsoft does not support autoreplies when forwarding rules are in place. To fix this, create a transport rule that excludes OOF messages from processing.

Why this happens

This issue occurs when autoreply (Out of Office) messages are not received by external recipients while Xink server-side is enabled.

Explanation:
Microsoft no longer supports sending autoreplies when a forwarding rule exists in the mail flow.

See Microsoft documentation

Solution: Exclude OOF messages

To resolve this, create a Microsoft 365 transport rule that excludes Out of Office (OOF) messages from being processed by Xink.

Step-by-step

1. Go to the Exchange Admin Center.
2. Navigate to Mail flow > Rules.
3. Click Add a rule.
4. Set the condition:
   • Message type is OOF
5. Add the action:
   • Set message header x-xink-handled to value yes

6. Enable the rule.
7. Set the priority to 0 (highest priority).

Result

Out of Office messages will bypass Xink processing and be delivered correctly to recipients.