Two-factor authentication is already enabled
POST /api/account/2fa/setup or /enable returned that 2FA is already enabled on the account.
Why this happens
twoFactorEnabled is true — no need to set up or turn on again. Use Turn off (if allowed) or manage from Settings. Distinct from “already set up” (secret exists but may be off) and from mandatory-login already enabled — sign in again.
Diagnose and fix
1. Refresh Account Settings — authenticator should show On.
2. To change devices: turn off (if allowed) or ask staff to Reset user 2FA / sessions, then set up again.
3. If site is mandatory, Turn off is blocked (Required on this site).