Microsoft 365 email groups
You can use Microsoft 365 email groups with Sophos Mailflow.
This can be useful if you only want to protect a subset of your Microsoft 365 mailboxes. You can have up to 10,000 mailboxes in a domain but if you only want to protect 200 of them, you can put them in a Microsoft 365 group.
You must create the group in your Microsoft 365 admin console before you set up Sophos Mailflow. See Create a group in the Microsoft 365 admin center.
The group type must be "Microsoft 365". Make sure you create it in the correct Microsoft 365 domain.
After the group is created, and the mailboxes added, we recommend you synchronize your directory service from Sophos Central. If you do this, your new Microsoft 365 group name appears as a suggestion when you configure Sophos Mailflow.
If you don't synchronize, you must make sure you enter the correct group name when you configure Sophos Mailflow.
Prevent duplicate scans after setting up groups
If you're setting up Sophos Mailflow on a domain that previously used Sophos Gateway, and you're using groups, we can't prevent both Sophos Mailflow and Sophos Gateway scanning email. It's important to disconnect the Sophos Gateway connection as soon as possible.
If you don't, Sophos Email Security scans each email twice. Your users will see double banners in emails, double entries in quarantine, and other confusing results.