{ "title": "Send an email from a Microsoft 365 alias", "excerpt": "I needed to reply to Chrome Web Store support from a specific address. The problem: web@amorem.com was only an Office 365 alias, and Outlook would always send from my primary address. Here's how I finally enabled sending from aliases.", "access": "free", "isAccessibleForFree": true, "requiresAccessPass": false, "locale": "en", "publishedAt": "2026-09-22T15:00:21.766Z", "updatedAt": "2026-09-22T17:10:21.438Z", "author": { "name": "Cédric TOURNIER", "username": "Amorem", "url": "https://mysaas.blog/en/@Amorem" }, "tags": [], "relatedSaas": [], "sources": [ { "title": "Microsoft Learn — Add another email alias for a user", "url": "https://learn.microsoft.com/en-gb/microsoft-365/admin/email/add-another-email-alias-for-a-user?view=o365-worldwide", "hostname": "learn.microsoft.com" }, { "title": "Microsoft Learn — Set-OrganizationConfig", "url": "https://learn.microsoft.com/en-us/powershell/module/exchangepowershell/set-organizationconfig?view=exchange-ps", "hostname": "learn.microsoft.com" } ], "urls": { "html": "https://mysaas.blog/en/@Amorem/send-an-email-from-a-microsoft-365-alias", "markdown": "https://mysaas.blog/en/@Amorem/send-an-email-from-a-microsoft-365-alias/md", "json": "https://mysaas.blog/en/@Amorem/send-an-email-from-a-microsoft-365-alias/json" }, "wordCount": 729, "images": [ { "url": "https://assets.mysaas.blog/posts/assets/2026-09-22/d22e46c0-614c-4550-a33b-bde517e42144.png", "alt": null, "title": null, "width": null, "height": null }, { "url": "https://assets.mysaas.blog/posts/assets/2026-09-02/e85a5217-7d11-4042-a4a2-4034c5c17e95.png", "alt": "Outlook Web - Addresses to send from with the alias web@amorem.com enabled", "title": null, "width": 2536, "height": 874 } ], "content": { "markdown": "I simply wanted to reply to an email from Chrome Web Store support.\n\nExcept that, this time, Google had a very specific requirement: the confirmation had to come from the original publisher account address, `web@amorem.com`.\n\nSmall problem: in my setup, `web@amorem.com` is not a separate mailbox. It's an alias of my primary Microsoft 365 mailbox, `cedric@amorem.com`.\n\nI receive emails sent to `web@amorem.com` just fine. But when I replied, Outlook would consistently put my primary address back in the sender field. In most situations that's not a problem. For a verification procedure where the sending address is part of the proof, it very much is.\n\n## Default behavior: an alias doesn't allow sending\n\nIn Exchange Online, a single mailbox can have one primary SMTP address and several proxy addresses — the so-called aliases. All of them land in the same inbox.\n\nIn my case:\n\n```\ncedric@amorem.com → primary address\nweb@amorem.com → alias\n```\n\nReceiving on the alias had always worked. However, when I chose `web@amorem.com` as the sender in Outlook, the received message always showed `cedric@amorem.com`.\n\nThis behavior is tied to an Exchange Online setting that, by default, can rewrite the address used for sending back to the mailbox's primary SMTP address.\n\n## The solution: SendFromAliasEnabled\n\nMicrosoft 365 has a specific setting that allows users to send from their proxy addresses. It is enabled at the Exchange Online organization level:\n\n```\nSet-OrganizationConfig -SendFromAliasEnabled $true\n```\n\nOnce enabled, Exchange Online should no longer systematically replace the alias used for sending with the primary SMTP address.\n\n## Doing it from a Mac\n\nI'm on macOS, so no need to look for a Windows machine. PowerShell works perfectly well on Mac.\n\nIn my case, Homebrew offered PowerShell Preview:\n\n```\nbrew install --cask powershell@preview\n```\n\nThen launch PowerShell:\n\n```\npwsh-preview\n```\n\nNext, install the Exchange Online module:\n\n```\nInstall-Module ExchangeOnlineManagement -Scope CurrentUser\n```\n\nConnect to the Microsoft 365 tenant with an account that has the necessary permissions:\n\n```\nConnect-ExchangeOnline\n```\n\nAnd finally:\n\n```\nSet-OrganizationConfig -SendFromAliasEnabled $true\n```\n\nYou can immediately verify the configuration:\n\n```\nGet-OrganizationConfig | Select-Object SendFromAliasEnabled\n```\n\nI wanted to see this:\n\n```\nSendFromAliasEnabled\n--------------------\nTrue\n```\n\n## Verify that the address is actually an alias of the mailbox\n\nSince Outlook initially kept playing tricks on me, I also checked the mailbox configuration itself:\n\n```\nGet-Mailbox cedric@amorem.com | Select-Object -ExpandProperty EmailAddresses\n```\n\nIn the Exchange output, you'll find in particular:\n\n```\nSMTP:cedric@amorem.com\nsmtp:web@amorem.com\n```\n\nThe distinction is useful: `SMTP:` in uppercase corresponds to the primary SMTP address and `smtp:` in lowercase to the proxy addresses.\n\n## What about Outlook?\n\nAfter enabling the setting on the Exchange side, you may need to give the change time to propagate and then restart Outlook or reconnect to Outlook Web.\n\nOnce the setting has propagated, Outlook Web shows the aliases under **Settings → Mail → Compose → Addresses to send from**. You simply check the address you want to make available in the *From* menu. In my case, `web@amorem.com` finally appeared and I was able to select it:\n\n![Outlook Web - Addresses to send from with the alias web@amorem.com enabled](https://assets.mysaas.blog/posts/assets/2026-09-02/e85a5217-7d11-4042-a4a2-4034c5c17e95.png)After propagation, Outlook Web lets you choose which aliases to display in the From field.\n\nThe behavior wasn't immediate: right after changing the Exchange configuration, typing `web@amorem.com` in the *From* field still produced a message sent from `cedric@amorem.com`. Then the section above appeared and sending from the alias worked.\n\nThat's probably the key takeaway if you land on this article after running the right command and feel like it did nothing: first check that `SendFromAliasEnabled` is indeed `True`, check that the alias is present in `EmailAddresses`, then let the change propagate before reconfiguring everything.\n\n## Why I didn't just create a second mailbox\n\nFor an address like `web@amorem.com`, creating and maintaining an independent Microsoft 365 mailbox would make no sense. I have several functional addresses that simply need to land in my primary inbox.\n\nAliases are perfect for that: a single mailbox, a single account, no additional license, and multiple email identities. You just need to know that allowing sending from those identities is a separate setting.\n\n## The command to remember\n\nIf you already have your Microsoft 365 aliases and your only problem is that Outlook keeps sending your emails from the primary address, start by checking this:\n\n```\nGet-OrganizationConfig | Select-Object SendFromAliasEnabled\n```\n\nIf the result is `False`, enable the feature:\n\n```\nSet-OrganizationConfig -SendFromAliasEnabled $true\n```\n\nIn my case, it was this small Exchange Online setting that finally allowed `web@amorem.com` to be genuinely used as the sender, and thus to finally respond correctly to the Chrome Web Store verification request.", "html": "

I simply wanted to reply to an email from Chrome Web Store support.

Except that, this time, Google had a very specific requirement: the confirmation had to come from the original publisher account address, web@amorem.com.

Small problem: in my setup, web@amorem.com is not a separate mailbox. It's an alias of my primary Microsoft 365 mailbox, cedric@amorem.com.

I receive emails sent to web@amorem.com just fine. But when I replied, Outlook would consistently put my primary address back in the sender field. In most situations that's not a problem. For a verification procedure where the sending address is part of the proof, it very much is.

Default behavior: an alias doesn't allow sending

In Exchange Online, a single mailbox can have one primary SMTP address and several proxy addresses — the so-called aliases. All of them land in the same inbox.

In my case:

cedric@amorem.com   → primary address\nweb@amorem.com      → alias

Receiving on the alias had always worked. However, when I chose web@amorem.com as the sender in Outlook, the received message always showed cedric@amorem.com.

This behavior is tied to an Exchange Online setting that, by default, can rewrite the address used for sending back to the mailbox's primary SMTP address.

The solution: SendFromAliasEnabled

Microsoft 365 has a specific setting that allows users to send from their proxy addresses. It is enabled at the Exchange Online organization level:

Set-OrganizationConfig -SendFromAliasEnabled $true

Once enabled, Exchange Online should no longer systematically replace the alias used for sending with the primary SMTP address.

Doing it from a Mac

I'm on macOS, so no need to look for a Windows machine. PowerShell works perfectly well on Mac.

In my case, Homebrew offered PowerShell Preview:

brew install --cask powershell@preview

Then launch PowerShell:

pwsh-preview

Next, install the Exchange Online module:

Install-Module ExchangeOnlineManagement -Scope CurrentUser

Connect to the Microsoft 365 tenant with an account that has the necessary permissions:

Connect-ExchangeOnline

And finally:

Set-OrganizationConfig -SendFromAliasEnabled $true

You can immediately verify the configuration:

Get-OrganizationConfig | Select-Object SendFromAliasEnabled

I wanted to see this:

SendFromAliasEnabled\n--------------------\nTrue

Verify that the address is actually an alias of the mailbox

Since Outlook initially kept playing tricks on me, I also checked the mailbox configuration itself:

Get-Mailbox cedric@amorem.com | Select-Object -ExpandProperty EmailAddresses

In the Exchange output, you'll find in particular:

SMTP:cedric@amorem.com\nsmtp:web@amorem.com

The distinction is useful: SMTP: in uppercase corresponds to the primary SMTP address and smtp: in lowercase to the proxy addresses.

What about Outlook?

After enabling the setting on the Exchange side, you may need to give the change time to propagate and then restart Outlook or reconnect to Outlook Web.

Once the setting has propagated, Outlook Web shows the aliases under Settings → Mail → Compose → Addresses to send from. You simply check the address you want to make available in the From menu. In my case, web@amorem.com finally appeared and I was able to select it:

\"Outlook

After propagation, Outlook Web lets you choose which aliases to display in the From field.

The behavior wasn't immediate: right after changing the Exchange configuration, typing web@amorem.com in the From field still produced a message sent from cedric@amorem.com. Then the section above appeared and sending from the alias worked.

That's probably the key takeaway if you land on this article after running the right command and feel like it did nothing: first check that SendFromAliasEnabled is indeed True, check that the alias is present in EmailAddresses, then let the change propagate before reconfiguring everything.

Why I didn't just create a second mailbox

For an address like web@amorem.com, creating and maintaining an independent Microsoft 365 mailbox would make no sense. I have several functional addresses that simply need to land in my primary inbox.

Aliases are perfect for that: a single mailbox, a single account, no additional license, and multiple email identities. You just need to know that allowing sending from those identities is a separate setting.

The command to remember

If you already have your Microsoft 365 aliases and your only problem is that Outlook keeps sending your emails from the primary address, start by checking this:

Get-OrganizationConfig | Select-Object SendFromAliasEnabled

If the result is False, enable the feature:

Set-OrganizationConfig -SendFromAliasEnabled $true

In my case, it was this small Exchange Online setting that finally allowed web@amorem.com to be genuinely used as the sender, and thus to finally respond correctly to the Chrome Web Store verification request.

", "text": "I simply wanted to reply to an email from Chrome Web Store support. Except that, this time, Google had a very specific requirement: the confirmation had to come from the original publisher account address, web@amorem.com . Small problem: in my setup, web@amorem.com is not a separate mailbox. It's an alias of my primary Microsoft 365 mailbox, cedric@amorem.com . I receive emails sent to web@amorem.com just fine. But when I replied, Outlook would consistently put my primary address back in the sender field. In most situations that's not a problem. For a verification procedure where the sending address is part of the proof, it very much is. Default behavior: an alias doesn't allow sending In Exchange Online, a single mailbox can have one primary SMTP address and several proxy addresses — the so-called aliases. All of them land in the same inbox. In my case: cedric@amorem.com → primary address web@amorem.com → alias Receiving on the alias had always worked. However, when I chose web@amorem.com as the sender in Outlook, the received message always showed cedric@amorem.com . This behavior is tied to an Exchange Online setting that, by default, can rewrite the address used for sending back to the mailbox's primary SMTP address. The solution: SendFromAliasEnabled Microsoft 365 has a specific setting that allows users to send from their proxy addresses. It is enabled at the Exchange Online organization level: Set-OrganizationConfig -SendFromAliasEnabled $true Once enabled, Exchange Online should no longer systematically replace the alias used for sending with the primary SMTP address. Doing it from a Mac I'm on macOS, so no need to look for a Windows machine. PowerShell works perfectly well on Mac. In my case, Homebrew offered PowerShell Preview: brew install --cask powershell@preview Then launch PowerShell: pwsh-preview Next, install the Exchange Online module: Install-Module ExchangeOnlineManagement -Scope CurrentUser Connect to the Microsoft 365 tenant with an account that has the necessary permissions: Connect-ExchangeOnline And finally: Set-OrganizationConfig -SendFromAliasEnabled $true You can immediately verify the configuration: Get-OrganizationConfig | Select-Object SendFromAliasEnabled I wanted to see this: SendFromAliasEnabled -------------------- True Verify that the address is actually an alias of the mailbox Since Outlook initially kept playing tricks on me, I also checked the mailbox configuration itself: Get-Mailbox cedric@amorem.com | Select-Object -ExpandProperty EmailAddresses In the Exchange output, you'll find in particular: SMTP:cedric@amorem.com smtp:web@amorem.com The distinction is useful: SMTP: in uppercase corresponds to the primary SMTP address and smtp: in lowercase to the proxy addresses. What about Outlook? After enabling the setting on the Exchange side, you may need to give the change time to propagate and then restart Outlook or reconnect to Outlook Web. Once the setting has propagated, Outlook Web shows the aliases under Settings → Mail → Compose → Addresses to send from . You simply check the address you want to make available in the From menu. In my case, web@amorem.com finally appeared and I was able to select it: After propagation, Outlook Web lets you choose which aliases to display in the From field. The behavior wasn't immediate: right after changing the Exchange configuration, typing web@amorem.com in the From field still produced a message sent from cedric@amorem.com . Then the section above appeared and sending from the alias worked. That's probably the key takeaway if you land on this article after running the right command and feel like it did nothing: first check that SendFromAliasEnabled is indeed True , check that the alias is present in EmailAddresses , then let the change propagate before reconfiguring everything. Why I didn't just create a second mailbox For an address like web@amorem.com , creating and maintaining an independent Microsoft 365 mailbox would make no sense. I have several functional addresses that simply need to land in my primary inbox. Aliases are perfect for that: a single mailbox, a single account, no additional license, and multiple email identities. You just need to know that allowing sending from those identities is a separate setting. The command to remember If you already have your Microsoft 365 aliases and your only problem is that Outlook keeps sending your emails from the primary address, start by checking this: Get-OrganizationConfig | Select-Object SendFromAliasEnabled If the result is False , enable the feature: Set-OrganizationConfig -SendFromAliasEnabled $true In my case, it was this small Exchange Online setting that finally allowed web@amorem.com to be genuinely used as the sender, and thus to finally respond correctly to the Chrome Web Store verification request." } }