返回结果:
{"code":110001,"data":{"err_detail":210202},"msg":"Internal Server Error","request_id":"e55d0353-2867-4c90-a62a-b6fa668ad67d"}

代码: 
func getAccessToken(appID, token, account string) (string, error) {
    url := "https://openaiapi.weixin.qq.com/v2/token"
    now := time.Now()
    timestamp := strconv.FormatInt(now.Unix(), 10)
    nonce := "abc" // Should generate a random nonce
    signature := generateSign(now, token, nonce, "")

    headers := map[string]string{
       "X-APPID":    appID,
       "request_id": uuid.NewString(),
       "timestamp":  timestamp,
       "nonce":      nonce,
       "sign":       signature,
    }

    bodyData := map[string]string{
       "account": account,
    }
    body, _ := json.Marshal(bodyData)

    response, err := util.SendPostRequest(url, headers, body)
    if err != nil {
       return "", err
    }

    return response, nil
}

func generateSign(timestamp time.Time, token, nonce, body string) string {
    sb := strings.Builder{}
    sb.WriteString(token)
    timeUnixStr := strconv.FormatInt(timestamp.Unix(), 10)
    sb.WriteString(timeUnixStr)
    sb.WriteString(nonce)
    sb.WriteString(getMd5String(body))
    resultStr := sb.String()
    result := getMd5String(resultStr)
    return result

}

func getMd5String(str string) string {
    bytes := []byte(str)
    sum := md5.Sum(bytes)
    return fmt.Sprintf("%x", sum)
}