diff --git a/backend/app/main.py b/backend/app/main.py
index 5a415a5..d81e1b1 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -9,6 +9,7 @@ import secrets
 import time
 import urllib.parse
 import urllib.request
+import urllib.error
 import uuid
 import io
 import zipfile
@@ -333,8 +334,11 @@ def _dingtalk_workbench_user(code: str) -> dict:
     try:
         with urllib.request.urlopen(token_request, timeout=10) as response:
             token_data = json.loads(response.read().decode("utf-8"))
+    except urllib.error.HTTPError as exc:
+        detail = exc.read().decode("utf-8", errors="replace")[:500]
+        raise HTTPException(status_code=502, detail=f"钉钉应用凭证校验失败：{detail}") from exc
     except Exception as exc:
-        raise HTTPException(status_code=502, detail="钉钉应用凭证校验失败，请稍后重试") from exc
+        raise HTTPException(status_code=502, detail=f"钉钉应用凭证校验失败：{exc}") from exc
     access_token = token_data.get("access_token")
     if not access_token:
         raise HTTPException(status_code=502, detail="钉钉未返回应用访问令牌，请检查应用权限")
@@ -347,8 +351,11 @@ def _dingtalk_workbench_user(code: str) -> dict:
     try:
         with urllib.request.urlopen(user_request, timeout=10) as response:
             user_data = json.loads(response.read().decode("utf-8"))
+    except urllib.error.HTTPError as exc:
+        detail = exc.read().decode("utf-8", errors="replace")[:500]
+        raise HTTPException(status_code=502, detail=f"无法读取钉钉用户信息：{detail}") from exc
     except Exception as exc:
-        raise HTTPException(status_code=502, detail="无法读取钉钉用户信息，请检查应用免登权限") from exc
+        raise HTTPException(status_code=502, detail=f"无法读取钉钉用户信息：{exc}") from exc
     if user_data.get("errcode", 0) not in (0, None):
         raise HTTPException(status_code=502, detail=f"钉钉用户信息读取失败：{user_data.get('errmsg', '请检查应用权限')}")
     return user_data.get("result") or user_data
diff --git a/frontend/index.html b/frontend/index.html
index 32c33c2..0365e01 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -7,7 +7,7 @@
   </head>
   <body>
     <div id="root"></div>
-    <script data-dingtalk-sdk="true" src="https://g.alicdn.com/dingding/dingtalk-jsapi/2.15.15/dingtalk.open.js"></script>
+    <script data-dingtalk-sdk="true" src="https://g.alicdn.com/dingding/dingtalk-jsapi/2.10.3/dingtalk.open.js"></script>
     <script type="module" src="/src/main.jsx"></script>
   </body>
 </html>
diff --git a/frontend/src/main.jsx b/frontend/src/main.jsx
index 9423235..4f6a519 100644
--- a/frontend/src/main.jsx
+++ b/frontend/src/main.jsx
@@ -86,16 +86,37 @@ function LoginPage({ onLogin }) {
   const [loading, setLoading] = useState(false);
   const [dingtalkLoading, setDingtalkLoading] = useState(false);
   const [autoDingtalkLogin, setAutoDingtalkLogin] = useState(false);
+  const [dingtalkLoginFailed, setDingtalkLoginFailed] = useState(false);
   const autoLoginStarted = useRef(false);
   const query = new URLSearchParams(window.location.search);
-  const inDingtalkWorkbench = /DingTalk|AliApp\(DT/i.test(navigator.userAgent || "") || query.get("from") === "dingtalk" || Boolean(window.dd || window.DingTalkPC);
+  const getDingTalkBridge = () => window.dd || window.DingTalkPC || window.dingtalk;
+  const inDingtalkWorkbench = /DingTalk|AliApp\(DT/i.test(navigator.userAgent || "") || query.get("from") === "dingtalk" || Boolean(getDingTalkBridge());
   function loadDingTalkSdk() {
-    if (window.dd) return Promise.resolve(window.dd);
+    if (getDingTalkBridge()) return Promise.resolve(getDingTalkBridge());
     return new Promise((resolve, reject) => {
       const existing = document.querySelector('script[data-dingtalk-sdk="true"]');
+      const urls = [
+        existing?.src || "https://g.alicdn.com/dingding/dingtalk-jsapi/2.10.3/dingtalk.open.js",
+        "https://g.alicdn.com/dingding/dingtalk-jsapi/2.15.15/dingtalk.open.js",
+      ];
+      let urlIndex = 0;
+      let settled = false;
       const finish = () => {
-        if (window.dd) resolve(window.dd);
-        else reject(new Error("钉钉JSAPI未加载，请确认工作台应用类型为H5微应用，并将 ask.dieya.net.cn 加入应用安全域名"));
+        if (settled) return;
+        if (getDingTalkBridge()) resolve(getDingTalkBridge());
+        else if (urlIndex < urls.length - 1) {
+          urlIndex += 1;
+          const fallback = document.createElement("script");
+          fallback.src = urls[urlIndex];
+          fallback.async = true;
+          fallback.dataset.dingtalkSdk = "true";
+          fallback.onload = finish;
+          fallback.onerror = finish;
+          document.head.appendChild(fallback);
+        } else {
+          settled = true;
+          reject(new Error("钉钉JSAPI未加载，请确认应用类型为H5微应用，并将 ask.dieya.net.cn 加入应用安全域名"));
+        }
       };
       if (existing) {
         existing.addEventListener("load", finish, { once: true });
@@ -104,7 +125,7 @@ function LoginPage({ onLogin }) {
         return;
       }
       const script = document.createElement("script");
-      script.src = "https://g.alicdn.com/dingding/dingtalk-jsapi/2.15.15/dingtalk.open.js";
+      script.src = urls[0];
       script.async = true;
       script.dataset.dingtalkSdk = "true";
       script.onload = finish;
@@ -114,7 +135,7 @@ function LoginPage({ onLogin }) {
     });
   }
   async function requestDingTalkAuthCode(corpId) {
-    const ding = (await loadDingTalkSdk()) || window.dd || window.DingTalkPC;
+    const ding = (await loadDingTalkSdk()) || getDingTalkBridge();
     return new Promise((resolve, reject) => {
       if (!ding) return reject(new Error("未检测到钉钉JSAPI，请将当前地址配置为钉钉H5微应用首页，并加入应用安全域名"));
       let settled = false;
@@ -131,8 +152,15 @@ function LoginPage({ onLogin }) {
       const invoke = () => {
         try {
           const requestAuthCode = ding.runtime?.permission?.requestAuthCode || ding.permission?.requestAuthCode;
-          if (!requestAuthCode) throw new Error("当前钉钉版本不支持工作台免登JSAPI");
-          requestAuthCode.call(ding.runtime?.permission || ding.permission, { corpId, onSuccess: success, onFail: failure });
+          if (requestAuthCode) {
+            requestAuthCode.call(ding.runtime?.permission || ding.permission, { corpId, onSuccess: success, onFail: failure });
+            return;
+          }
+          if (typeof ding.getAuthCode === "function") {
+            ding.getAuthCode({ onSuccess: success, onFail: failure });
+            return;
+          }
+          throw new Error("当前钉钉版本不支持工作台免登JSAPI");
         } catch (error) {
           failure(error);
         }
@@ -142,21 +170,10 @@ function LoginPage({ onLogin }) {
       window.setTimeout(() => failure(new Error("钉钉免登请求超时，请确认应用已发布并开通免登权限")), 10000);
     });
   }
-  async function loginWithDingTalk() {
-    setDingtalkLoading(true);
-    setError("");
-    try {
-      const result = await api("/api/admin/auth/dingtalk/start");
-      window.location.assign(result.data.url);
-    } catch (err) {
-      setError(err.message);
-      setDingtalkLoading(false);
-      setAutoDingtalkLogin(false);
-    }
-  }
   async function loginWithDingTalkWorkbench() {
     setDingtalkLoading(true);
     setError("");
+    setDingtalkLoginFailed(false);
     try {
       const config = await api("/api/admin/auth/dingtalk/config");
       if (!config.data?.enabled || !config.data?.corp_id) throw new Error("钉钉工作台免登尚未配置，请联系管理员");
@@ -165,6 +182,7 @@ function LoginPage({ onLogin }) {
       onLogin(result.data.user);
     } catch (err) {
       setError(err.message);
+      setDingtalkLoginFailed(true);
       setAutoDingtalkLogin(false);
       setDingtalkLoading(false);
     }
@@ -188,7 +206,7 @@ function LoginPage({ onLogin }) {
     }
   }
   useEffect(() => {
-    if (!inDingtalkWorkbench || query.get("dingtalk") === "success" || autoLoginStarted.current) return;
+    if (!inDingtalkWorkbench || autoLoginStarted.current) return;
     autoLoginStarted.current = true;
     setAutoDingtalkLogin(true);
     loginWithDingTalkWorkbench();
@@ -196,6 +214,23 @@ function LoginPage({ onLogin }) {
   if (autoDingtalkLogin) {
     return <div className="loading-screen">正在验证钉钉身份…</div>;
   }
+  if (inDingtalkWorkbench && dingtalkLoginFailed) {
+    return (
+      <main className="login-shell">
+        <section className="login-card dingtalk-workbench-card">
+          <div className="brand-mark"><MessageCircle size={28} /></div>
+          <div className="brand-title">{Z.brand}</div>
+          <h1>钉钉工作台免登</h1>
+          <p className="login-subtitle">正在使用当前钉钉账号验证身份，不需要输入后台账号密码。</p>
+          <div className="form-error">{error || "钉钉免登失败，请稍后重试"}</div>
+          <button className="primary-button login-button" type="button" onClick={() => { setAutoDingtalkLogin(true); loginWithDingTalkWorkbench(); }} disabled={dingtalkLoading}>
+            {dingtalkLoading ? "正在验证钉钉身份…" : "重新验证"}
+          </button>
+          <div className="login-hint">请从钉钉工作台打开此应用，并确认应用已发布、配置安全域名和免登权限。</div>
+        </section>
+      </main>
+    );
+  }
   return (
     <main className="login-shell">
       <div className="login-decoration">
@@ -210,10 +245,7 @@ function LoginPage({ onLogin }) {
         <div className="brand-title">{Z.brand}</div>
         <h1>{Z.backend}</h1>
         <p className="login-subtitle">从钉钉工作台进入，使用钉钉身份安全登录</p>
-        <button className="dingtalk-login-button" type="button" onClick={inDingtalkWorkbench ? loginWithDingTalkWorkbench : loginWithDingTalk} disabled={dingtalkLoading}>
-          {dingtalkLoading ? "正在验证钉钉身份…" : "使用钉钉登录"}
-        </button>
-        <div className="login-divider"><span>或使用后台账号</span></div>
+        {!inDingtalkWorkbench && <div className="login-divider"><span>运营后台账号登录</span></div>}
         <form onSubmit={submit} className="login-form">
           <label>
             {Z.username}