Office 365 - Outbound Connector Bug Workaround


As of March 2, 2018, a few partners have informed us of outbound connector configurations that would not validate successfully. The cause of the failure is the configuration setting that instructs the connector to be used for all domains. Microsoft is aware of the problem, but no estimate of a resolution has been given.

This article describes the steps to implement a workaround using a transport rule with the outbound connector.

Applies to:

Office 365 (O365), Exchange Online


The article assumes you have tried to follow the directions in the Outbound Connector Configuration article and received an error during the validation of Step 10. You will need to choose 'Only when I have a transport rule setup that redirects messages to this connector' in Step 5 before you configure this transport rule.

The domain is also already configured in the Mailprotetor Console and is ready for outbound mail flow.

Configuration Steps

Add the Transport Rule

  1. Open the Office 365 Admin Center and navigate to the Exchange Admin center, as shown in Figure 1. This link will open a new tab in your browser with the Exchange Admin Center.

    Fig. 1
  2. Find and click the 'rules' link under the mail flow options, as shown in Figure 2. The link takes you to the rules for the domain.

    Fig. 2

  3. You may have other rules already listed. Click on the 'plus icon' to add a new rule and select 'Create a new rule' as shown in Figure 3.

    Fig. 3

  4. The new rule dialog box will open. Complete the settings in the dialog box as shown in Figure 4, then click the 'Save' button.

    NOTE: You may need to click the 'More options...' link at the bottom of the new rule dialog box to complete the configuration of the rule.

    ERROR NOTE: If you receive an error message that states - The connector "connector name" is not enabled. Please enable it or specify a different connector. Please go back to the connectors page and turn on the connector you created for outbound email.

    Fig. 4

  5. The transport rule will be saved and listed on the rules page.

Implementation Note

The use of the transport rule to redirect messages going to recipients outside the domain is a workaround for the typical outbound connector configuration. This workaround can be left in place as a permanent configuration, but Mailprotector will announce when the connector bug has been fixed by Microsoft for those that want to follow the typical setup.

If you have more questions about this, please contact Mailprotector Support.

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