Thunderbird is not a recommended desktop email client, as it does not support the full range of features available with your mailbox. Microsoft Outlook is the recommended and supported desktop email client for Windows and Mac. This information is being provided primarily for those who choose to use the Linux operating system and are unable to use Microsoft Outlook.
You must first submit an IT Support request to have SMTP Authentication enabled on your account. Without that, you will be unable to send mail using Thunderbird.
Note: There have been reports of issues with OAuth2 authentication and IPv6. If you are having trouble connecting to your account with Thunderbird, try changing one or both of the following settings under Settings > General > Edit Configuration:
network.dns.disableIPv6 = true
network.dns.ipv4OnlyDomains = office365.com
Once SMTP Authentication is enabled on your account by ITS, perform the following steps to configure your account in Thunderbird:
- Launch Thunderbird
- Select Tools > Account Settings
- Select Account Actions > Add Mail Account...

- Type in your name and email address, uncheck Remember password, then select Configure Manually...

- Complete the form with the appropriate information:
- Incoming
- Protocol: IMAP
- Server: outlook.office365.com
- Port: 993
- SSL: SSL/TLS
- Authentication: Autodetect
- Username: <username>@unbc.ca
- Outgoing
- Server: smtp.office365.com
- Port: 587
- SSL: STARTTLS
- Authentication: Autodetect
- Username: <username>@unbc.ca
- Select Advanced config, then click OK on the Confirm Advanced Configuration popup
- Select OAuth2 in the Authentication Method dropdown

- Select Outgoing Server (SMTP), then choose the smtp.office365.com entry and then Edit...

- Enter a Description if you want, then select OAuth2 in the Authentication method dropdown, then OK

- Verify that the account is using the correct SMTP server
