Understanding the Email Addresses Used by Microsoft 365 Groups and Teams

There’s Email and There’s Email

I’ve seen some confusion over the email addresses used by Microsoft 365 Groups and Teams. This note gives a quick summary of the situation.

Email Addresses for a Microsoft 365 Group

Every Microsoft 365 group has at least one email address, but might have several, all of which can be used to route email to the group. We can retrieve the addresses from the group’s EmailAddresses property.

Get-UnifiedGroup -Identity "PL Test" | Select -ExpandProperty EmailAddresses
SPO:SPO_34be8c3b-3b4b-42e5-9e27-569045512c97@SPO_b662313f-14fc-43a2-9a7a-d2e27f4f3478
smtp:PLTest@office365itpros.onmicrosoft.com
SMTP:PLTest@office365itpros.com

The SMTP proxy addresses assigned to Microsoft 365 groups are used by Exchange Online to route email. Exchange Online creates the set of SMTP addresses during the creation of a new Microsoft 365 group. The set of addresses might be affected by the existence of an email address policy for groups. In all cases, one of the addresses must be a MOERA (Microsoft Online Email routing address), which comes from the tenant service domain (xxx.microsoft.com). Another of the addresses has the prefix highlighted, meaning that this address is the primary address of the type. For SMTP addresses, this means that the address is stamped on outbound messages sent by the group. The primary SMTP address for the group is also stored in the PrimarySMTPAddress property. For example:

Get-UnifiedGroup -Identity "PL Test" | Select PrimarySMTPAddress

PrimarySmtpAddress
------------------
PLTest@office365itpros.com

Sending to a Group

When you send email to a Microsoft 365 group, Exchange Online treats the group like a distribution list and delivers messages to any of the group members who subscribe for updates. A copy of the message is also delivered to the group mailbox, where it creates a new conversation in the group inbox. To find out which members receive updates sent to a group, run the command (there’s no UI to expose this list):

Get-UnifiedGrouplinks -Identity "PL Test" -LinkType Subscribers

Email for Teams Channels

If the Email Integration setting is enabled for Teams in a tenant, (Figure 1) you can generate email addresses for channels and use those addresses to send email to the channels. It’s important to underscore that the recipient is a channel and not the members of the team.

To generate an email address for a channel, select the channel and then take the Get Email Address choice in the […] menu. If an email address doesn’t already exist, a new one is generated (Figure 2). Any member of a team (except guests) can generate an email address for a channel.

The email address does not belong to any domain associated with the Microsoft 365 tenant. Instead, it’s in a part of Office 365 managed by Microsoft. The address is intended to be obscure to avoid casual spamming, so we end up with something like this:

General – Project Condor <95c133a3.office365itpros.com@emea.teams.ms>

If a channel is spammed, just remove the email address and generate a new one or include the spamming domain in the blacklist in the Email Integration section of Teams settings.

The email address for a Teams channel can be used much like any other email address. For instance, you can add it as a mail contact to the Exchange GAL or include it in the membership of a distribution list.

Sending to a Channel

When you send email to a channel, the message arrives in a special form of mailbox. A connector then picks up the new message and imports it into Teams, where it shows up in two places:

• A new conversation in the channel.
• A copy of the message (.eml file) and any attachments are stored in the SharePoint site belonging to the team. You’ll find these items in the Email Messages folder (Figure 3) under the folder for the channel. (Note: In February 2021, Microsoft changed how it stores copies of messages received by channels in SharePoint Online).

Because the messages and attachments are in SharePoint, they are indexed and available for compliance purposes.

Copies of messages sent to a channel are never delivered to team members. The email address is for a channel and does not act like a distribution list. If you want to send email to everyone in a team, use the email address assigned to the Microsoft 365 group used by the team. If the recipients subscribe to the group, they’ll get the message. If not, they won’t unless you use PowerShell to read the group membership and add each member as a recipient for the message.

---

For more information, read Office 365 for IT Pros to learn about much more about Microsoft 365 Groups and Teams. Obviously, we have a lot more to say about these and other associated topics than can be covered in a 600-word blog post.