what AI says
"To add an app-specific password to Fantastical on macOS, you must generate the password from your Apple Account and enter it into the app settings. [1]
Step 1: Generate the App-Specific Password
- Go to Apple Account Management and sign in with your Apple Account.
- In the Sign-In and Security section, select App-Specific Passwords.
- Click the + (plus) button.
- Type a label for the password (for example, Fantastical) and click Create.
- Copy or write down the generated password (it looks like xxxx-xxxx-xxxx-xxxx). [1]
Step 2: Add the Password to Fantastical on macOS
- Open Fantastical on your Mac.
- Go to Fantastical in the top menu bar, then click Settings (or Preferences) → Accounts.
- Add your iCloud account (or select your existing iCloud account if you are re-adding it).
- Enter your primary Apple Account email address.
- Paste or type the app-specific password into the App-Specific Password field. [1, 2]
(Note: Two-factor authentication must be enabled on your Apple Account for app-specific passwords to work). [1]
If you run into any issues during the setup, let me know if Fantastical is giving a specific error message or if you need help removing and re-adding the account."
and then
Fantastical - Adding Your iCloud Account
Flexibits | Fantastical | iCloud Authentication
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adding app-specific password for Fantastical macos - Google-