Yahoo Mail API/IMAP service recommends third-party applications like Canopy to use their OAuth-2.0 authentication to access a Yahoo Mail account. Unlike Gmail and Outlook 365 which make their OAuth-2.0 authentication flow public, Yahoo has an internal review process it must perform before it allows third-party applications to access its OAuth-2.0 APIs.
Connect a Yahoo Email Account
1. To get started, log in to your Yahoo email account.
2. Click your profile bubble in the top right and select Account info.
3. Click Account Security.
4. Scroll to Other ways to sign in and click Generate app password to get a one-time password for Canopy.
If you have already created a one-time password for other apps, click Manage App Passwords.
5. Click Get started.
6. Enter Canopy as the app's name.
7. Click Generate password.
8. Copy the generated code from Yahoo, and paste it into the password field of Canopy.
9. Click Connect account in Canopy.
Canopy will connect to your Yahoo account.
Then, return to the Connect an Email Account article!