Send & Receive Issues

How to Send Email from an Address in Another Microsoft 365 Tenant in Outlook

Guest Writer Oct 10, 2026 869 views

Question details

The user needs to send emails from an address belonging to a different Microsoft 365 tenant.

How to Send Email from an Address in Another Microsoft 365 Tenant

Product: Microsoft 365 / Outlook
Device & OS: not provided
Scenario: Configuring an email account or alias to send messages from a domain registered in another Microsoft 365 tenant.
Observed behavior: An email domain cannot be active in two Microsoft 365 tenants simultaneously, requiring global administrators to properly verify domains and assign aliases to users.

Before you start

Ensure you have global administrator privileges in the target Microsoft 365 tenant, as you will need to add and verify the domain before configuring user aliases.

Solution 1Recommended

Configure Domain and Assign Alias via Microsoft 365 Admin Center

The standard method requires a global admin to verify the domain in the correct tenant and assign the email address as an alias to the user.

A single verified domain cannot exist in two Microsoft 365 tenants simultaneously. You must first ensure the domain is added to the appropriate tenant where the user resides before configuring the alias.

Add and verify the domain

Log into the Microsoft 365 Admin Center as a global administrator. Navigate to Settings, then Domains, and follow the prompts to add and verify your required domain in the appropriate tenant.

Assign the alias to a user

Go to Users > Active users, select the user you want to configure, and click 'Manage username and email'. Add the new email address associated with the verified domain as an alias for the user.

Send from the new alias in Outlook

Open Outlook (web or desktop), enable the 'From' field in a new message, and select or type the newly added alias to send emails.

Configure Domain and Assign Alias via Microsoft 365 Admin Center

Propagation Time: It may take up to 24 hours for new aliases and domain settings to fully sync across Microsoft 365 services and appear in Outlook.

Solution 2

Automate Alias Assignment using PowerShell

Ideal for organizations needing to assign aliases to multiple users simultaneously across a tenant.

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Frequently Asked Questions

Can I have the same domain active in two different Microsoft 365 tenants?

No, a verified domain cannot be configured in two Microsoft 365 tenants simultaneously. It must be entirely removed from one tenant before it can be fully verified and routed in another.

How do I show the 'From' field in Outlook to select my alias?

In Outlook for Desktop, open a new email, navigate to the 'Options' tab on the ribbon, and click 'From' to display the field. You can then click the 'From' dropdown to select or type your newly assigned alias.

Can I automate the process of adding aliases for all my users?

Yes, global administrators can automate alias assignments across multiple users using PowerShell scripts (Exchange Online cmdlets) or the Microsoft Graph API, rather than updating each user manually in the Microsoft 365 Admin Center.

Outlook & Email Problems