Yahoo users might have trouble authenticating their accounts if they haven't changed a setting within their Yahoo account.
Yahoo suggests that you temporarily "allow apps that use less secure sign in" to authenticate with 3rd party apps like Nylas.
To give temporary access while updating:
- Sign in to Yahoo Mail.
- Go to your "Account security" settings.
- Turn on Allow apps that use less secure sign in.
- Once the feature is turned on, you'll get regular alerts reminding you to turn it off. To do so, just follow the steps above and turn off "Allow apps that use less secure sign in."
- You also might need to create an app-specific password and authenticate the account with Nylas if you have 2FA enabled.