This is a guide for setting up the Mozilla Thunderbird email client with your UWaterloo.ca email.
"OAuth2" does not become an authentication option until you set the server.
On Arch: sudo pacman -S thunderbird
On Debian: sudo apt install thunderbird
On Fedora: sudo dnf install thunderbird
From Flathub: flatpak install flathub org.mozilla.Thunderbird
On macOS/Windows: Download Thunderbird from https://www.thunderbird.net/
Open Thunderbird. On first run, Thunderbird should ask you to set up an existing email address.
Fill in your information, using your @uwaterloo.ca email address. Click Configure manually.
First, set the hostnames.
Incoming server:
Outgoing server:
The hostname needs to be set for you to choose OAuth2 as the authentication method. Now fill in all the information.
Incoming server:
Outgoing server:
Click Re-test to check these settings. Click Done to attempt to log in.
Thunderbird will now open a web view with a login page asking you to sign in to your University of Waterloo account. Enter your password and click Sign in.
Complete the Duo two-factor authentication.
If this is your first time connecting Thunderbird to your account, Microsoft will ask if you want to grant permission for it to act as a third-party app. Accept this request.
In the Thunderbird Account Setup menu, click Done again to try to log in. This time, you should log in successfully.
How to Configure Thunderbird for Office 365 Using IMAP (Oauth2)