Office 365 (Thunderbird) - Using Send As Permissions

Best Effort Support Only

This document contains instructions on using a non-Microsoft email client, such as Apple Mail or Thunderbird. Microsoft does not recommend these clients for use with Office 365, and there are often significant limitations in client functionality as a result.

Because of this, the DoIT Help Desk is only able to offer best effort support for these clients, and certain issues may require the use of a Microsoft client in order to be resolved. For more information on Office 365 client support, please see: Office 365 - Which clients/protocols will be supported?.

This document will explain how to utilize your send-as permissions in order to send emails from another email address. In order to do this Thunderbird uses the Manage Identities feature. This also works for aliases and alternate addresses on your account.

Note: This document assumes you already have send-as permissions for the account you are trying to send emails for. If you have not been granted send-as permissions, you will need to have the owner of account you are trying to send messages for grand you send-as permissions. Refer to the following document: Office 365 - Manage Full Mailbox, Send As, and Send on Behalf of Permissions. If you are sending from an alias or alternate address, you do not need send-as permissions.

Configure Account Settings

  1. Open Mozilla Thunderbird.
  2. In the left hand pane, select the account with send-as permissions.
  3. In the Accounts menu, click on View settings for this account.

    Click View Settings For This Account

  4. In the "Account Settings" window, click Manage Identities....

    Click Manage Identities

  5. Select the account with send-as permissions and then click the Add... button.

    Click Add

  6. The "Identity Settings" window will open, fill in the following fields:
    • Your Name: Enter the name of the account you are sending emails for.
    • Email Address: Enter the email of the account you are sending emails for.
    • Reply-to Address (Optional): If you want the reply-to address to be different, enter the email address you want in to this field.
  7. Click OK at the bottom of the "Identity Settings" window, click Close in the "Identities" window, and click OK in the "Account Settings" window.

Sending An Email From Another Account

  1. Click the Write button to compose a new email.
  2. Click the current email address in the "From:" field and select the address you would like to send as.

    Change The From Field

  3. You can now send an email as the selected email address.

    Note: If you set a Reply-To email address when configuring "Account Settings", it will automatically appear when selected the email address in the "From:" field.