On-premise mail shows as outbound in office 365

Question

Hi we have a Hybrid exchange environment. All mails which are sent from our on-premise exchange server to office 365 are treated as external?

I have already tried to set some values to $true on the on-premise remotedomain (isinternal, trustedmailoutboundenabled, targetdeliverydomain) but mails are still showing up as external (we have created a rule to add a disclaimer when mail is from outside the organisation).

Also in the headers we see: X-MS-Exchange-Organization-AuthAs: Anonymous

Can someone help me with this issue?

Thanks in advance

Answer 1

Can you paste the complete values of the send connector you use to send to 365 from on-prem ( removing any domain info)

get-sendconnector <Connector to 365> |FL

Make sure this is set to $true

-CloudServicesMailEnabled $true

Is there a matching inbound connector on the 365 side?

More info:

https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/use-connectors-to-configure-mail-flow/set-up-connectors-to-route-mail#1-set-up-a-connector-from-your-email-server-to-microsoft-365-or-office-365

Answer 2

Did you run Hybrid Configuration wizard successfully? In general, the required connectors can be created automatically when you run HCW.

As AD-7937 mentioned, please check the configuration of the send connector used for outbound to O365. Make sure it's enabled and CloudServicesMailEnabled is set to true.

Here are default settings of the send connector "Outbound to Office 365" created automatically by running HCW:

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