Error with Teams invitations after adding custom domain to Entra ID

Antonis Esepenoglou 0 Reputation points
2024-04-15T12:19:18.4833333+00:00

How can I resolve an issue where Teams invitations between employees fail after adding a custom domain to our Entra ID? The error message states that the invited user cannot be found despite existing in the organization. Do I need to configure DNS records so that emails are sent to the correct server for search? We do not use Microsoft Exchange or Office 365, but instead have an on-premise mail solution.

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Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. LiweiTian-MSFT 14,220 Reputation points Microsoft Vendor
    2024-04-16T02:20:08.82+00:00

    Hi @Antonis Esepenoglou

    Please ensure that the custom domain is correctly added to Microsoft Entra ID, please refer to https://learn.microsoft.com/en-us/entra/identity/users/domains-manage

    If you want to invite internal users to join B2B collaboration. You can use the Microsoft Entra admin center, PowerShell, or the invitation API to send a B2B invitation to the internal user. Some things to note:

    1.Before you invite the user, make sure the property of the internal user object (the user's Email property in the Microsoft Entra admin center) is set to the external email address they'll use for B2B collaboration. If the internal user has an existing mailbox, you can't change this property to an external email address. You must update their attributes in the Exchange admin center.User.Mail

    2.When you invite the user, an invitation is sent to the user via email. If you're using PowerShell or the invitation API, you can suppress this email by setting to . Then you can notify the user in another way. Learn more about the invitation API.SendInvitationMessageFalse

    3.When the user redeems the invitation, the account they're using must match the domain in the property. Otherwise, some services, such as Teams, won't be able to authenticate the user.User.Mail

    Please refer to Invite internal users to B2B collaboration

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