diff --git a/crates/presenter/src/host/accounts/failure.rs b/crates/presenter/src/host/accounts/failure.rs
index 541e071..b04833e 100644
--- a/crates/presenter/src/host/accounts/failure.rs
+++ b/crates/presenter/src/host/accounts/failure.rs
@@ -5,6 +5,8 @@
 
 use unlucky_core::auth::AuthError;
 
+use unlucky_core::auth::BodyKind;
+
 use crate::dto::{AccountNoticeCode, LoginFailure};
 
 /// 账户写操作的失败：**结构化码 + 原文**（原文只进日志/详细信息，不上屏）。
@@ -44,10 +46,17 @@ pub(super) fn classify(error: &AuthError) -> LoginFailure {
                 LoginFailure::Denied
             }
         }
+        // 只看 `ResponseDetail` 的**结构化字段**（status / kind / server_message），
+        // 不把整条错误 Debug 成字符串再去扫——那会把中文 `what`/`digest` 也算进判据里。
         AuthError::Response(detail) => {
-            let blob = format!("{detail:?}");
-            if mentions_whitelist(&blob) {
+            let server = detail.server_message.as_deref().unwrap_or_default();
+            let digest = detail.digest.as_str();
+            if mentions_whitelist(server) || mentions_whitelist(digest) {
                 LoginFailure::NotWhitelisted
+            } else if detail.status >= 500 || matches!(detail.kind, BodyKind::Html | BodyKind::Text)
+            {
+                // 5xx / 拦截页：服务器或链路出了问题，不是「它拒绝了你」。
+                LoginFailure::Unreachable
             } else {
                 LoginFailure::Denied
             }
@@ -67,3 +76,51 @@ pub(super) fn mentions_whitelist(text: &str) -> bool {
         || lowered.contains("whitelist")
         || lowered.contains("not approved")
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use unlucky_core::auth::body::ResponseDetail;
+
+    fn response(status: u16, kind: BodyKind, server_message: Option<&str>) -> AuthError {
+        AuthError::Response(Box::new(ResponseDetail {
+            step: "xsts".to_string(),
+            what: "XSTS 授权".to_string(),
+            status,
+            content_type: None,
+            kind,
+            server_message: server_message.map(str::to_string),
+            digest: "digest".to_string(),
+        }))
+    }
+
+    /// 403 带 AADSTS 码 → 白名单未批；403 不带 → 一般性拒绝。
+    #[test]
+    fn aadsts_markers_win_over_the_generic_denial() {
+        assert_eq!(
+            classify(&response(
+                403,
+                BodyKind::Json,
+                Some("AADSTS7000218: app not approved")
+            )),
+            LoginFailure::NotWhitelisted
+        );
+        assert_eq!(
+            classify(&response(403, BodyKind::Json, Some("invalid_grant"))),
+            LoginFailure::Denied
+        );
+    }
+
+    /// 5xx 与「拦截页」（HTML/纯文本）归「连不上」，不是「服务器拒绝了你」。
+    #[test]
+    fn upstream_failures_and_intercept_pages_are_unreachable() {
+        assert_eq!(
+            classify(&response(503, BodyKind::Json, None)),
+            LoginFailure::Unreachable
+        );
+        assert_eq!(
+            classify(&response(200, BodyKind::Html, None)),
+            LoginFailure::Unreachable
+        );
+    }
+}