# AI告诉南非纳税人使用FNB eFiling进行SARS申报，却未提及FNB银行应用的30秒OTP有效期，导致申报失败

- **ID:** `banking/fnb-otp-expiry-sars`
- **领域:** banking
- **类别:** auth_error
- **错误码:** `FNB-OTP-EXPIRED-30S`
- **验证级别:** ai_generated
- **修复率:** 90%

## 根因

FNB银行应用为eFiling身份验证生成的有效期仅为30秒的OTP；如果用户未能在30秒内输入OTP，SARS会话将超时，申报被拒绝

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| FNB Banking App v10.2 | active | — | — |
| SARS eFiling 2024 | active | — | — |
| FNB OTP Service 2.0 | active | — | — |

## 解决方案

1. ```
   Before clicking 'Request OTP' on SARS eFiling, have the FNB app open and ready; click the button, immediately switch to the app, copy the OTP, and paste it within 30 seconds using a password manager
   ```
2. ```
   Use a secondary device (e.g., tablet) to display the SARS page while the phone shows the OTP, reducing switching time
   ```
3. ```
   If the OTP expires, start a fresh SARS session by closing the browser tab, clearing cookies, and re-logging in before requesting a new OTP
   ```

## 无效尝试

- **** — The SARS session remains tied to the original OTP request; new OTPs still expire in 30 seconds and the session may lock after 3 failed attempts (90% 失败率)
- **** — FNB's SMS OTP also has a 30-second expiry for eFiling; there is no longer-lived alternative for SARS authentication (95% 失败率)
- **** — The SARS session token is invalidated after the first OTP request; a new session must be started from the SARS login page (85% 失败率)