new outlook email address set up

Hi Ben Clarke,

I understand that the newly created Outlook.com address is showing as an outlook_[long series]@outlook.com address, even though the iPhone Mail account settings show the address you expected. This can be confusing, especially when the display looks correct on the phone but not in Outlook.com.

Please note that this is a user-to-user forum, so contributors here can share guidance based on available settings and documentation but cannot directly access or change your Microsoft account.

The Q&A Assist answer is generally correct that this is usually related to the Microsoft account alias or default sending address, rather than the iPhone Mail display name. Have you had a chance to check the alias or primary address setting suggested there? I would like to add one important point without repeating those same steps.

Please check the Microsoft account alias settings from a browser:

1. Go to Manage how you sign in to Microsoft and sign in with the affected account.
2. Under the account aliases section, check whether the email address you want to use is listed.
3. If it is listed, select Make primary next to that address.
4. After changing it, sign out and sign back in to Outlook.com, then test sending a new message from https://outlook.live.com/.
5. In Outlook.com, when composing a new message, select Options > Show From, then choose the address you want to send from. You can also review this setting here: Send email from a different address in Outlook.com.

If the address you want is not listed as an alias, you may need to add it first. Please see: Add or remove an email alias in Outlook.com.

Also, please avoid posting the full generated Outlook address or any personal email address publicly. If you need to share screenshots, please mask the full email address first.

If the alias is already set as primary but Outlook.com still sends from the generated outlook_[long series]@outlook.com address, please reply with whether this is a newly created Outlook.com address or an address from another provider added to a Microsoft account. That detail will help narrow down the next step.

The behavior is typically caused by how the Outlook.com / Microsoft account and aliases are set up, not by the iPhone Mail settings.

When a non-Outlook address (or a new alias) is registered on a Microsoft account, Outlook can show or send mail using an outlook_[long series of letters and numbers]@outlook.com address instead of the friendly address that was just created. This is a known issue when a third‑party or secondary alias is involved.

To fix it, the account needs to be set up as a standard IMAP/POP account (using the actual email address and server settings) instead of relying on the automatically detected Outlook.com/Microsoft account configuration:

1. In Outlook (on Windows):
   1. Close Outlook.
   2. Press Windows key + R, type outlook /profiles and select OK.
   3. In the Choose Profile window, select Options > New.
   4. Enter a new profile name and select OK.
   5. Choose Advanced options > Let me set up my account manually.
   6. Select IMAP or POP and enter the server settings provided by the email provider.
   7. Complete setup and then, in Choose Profile, set this new profile as default.
2. On iOS (if using Outlook for iOS):
   1. Open Outlook for iOS.
   2. Go to Settings > Accounts > Add Account > Email Account.
   3. Enter the desired email address and tap Add Account.
   4. On the Select your email provider screen, choose IMAP.
   5. Turn on Use Advanced Settings and enter the correct incoming/outgoing server details.

This ensures the correct email address is used for sending and displaying in apps and avoids the outlook_[numbers]@outlook.com format.

If the account is an Outlook.com address with multiple aliases, also verify which alias is primary in the Microsoft account; using a third‑party or different alias as primary can trigger this behavior.

References:

• Set up the Outlook app for iOS