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SpamHero can be used to filter both inbound and outbound mail for your Microsoft 365 account. This article outlines the steps for setting up Microsoft 365 to relay your outbound mail through SpamHero.

SPF record setup

To ensure the successful delivery of your mail, include SpamHero in your domain's SPF record. If you don't have an SPF record then you'll want to create one now:

SpamHero settings

The Microsoft 365 Connector feature must be enabled in your SpamHero control panel before it will work.

  1. Login to the SpamHero control panel and navigate to Outbound > Outbound settings (
  2. In the Smart host setup area, turn on Enable outbound smart host relay
  3. Turn on Allow Microsoft 365 Outbound Connector


Microsoft 365 settings

After you have enabled the Microsoft 365 Connector feature in your SpamHero control panel, you can follow these steps to create the connector in the Exchange Admin Center. Your outbound mail will immediately begin to send through the SpamHero servers as soon as

  1. Connectors window
    Navigate to the Exchange Admin Center (,
    From there, go to Mail flow > Connectors (
    Click on the + Add a connector button

  1. New connector window
    For Connection from, select Office 365.
    For Connection to, select Partner organization
    Click the Next button

  1. Connector name window
    Give the Connector a name, like Send outbound mail through SpamHero
    Click the Next button.

  2. Use of connector window
    Select Only when email messages are sent to these domains
    Enter an aserisk (*) in the input box to send all outbound mail through SpamHero servers.
    Click the plus button, to the right
    Click the Next button

  1. Routing window
    (You must be logged in to read this portion of the article)
  2. Security restrictions window
    Click on the Next button to accept the default security restrictions

  1. Validation email window
    Enter any valid email address that is outside of your domain.
    Click the plus button, to the right
    Click the Validate button (a validation email will be sent to the address you entered above)
    After the validation is finished, click the Next button
    Important notes:
    • The validation process can take up to a few minutes.
    • Sometimes, a Validation failed error will appear. It should be safe to ignore but be sure to test your outbound mail just to be sure.

      To ignore the Validation failed error, click on the Next button. A confirmation banner will appear. Simply click on the Yes button:

  2. Review connector window
    Review the connector settings to confirm that everything looks good.
    Click the Create connector button

  3. Send a test
    Just to be on the safe side, send a "test" message to an email address that is outside of your domain.
Last updated October 31, 2023