diff --git a/backend/api_service/app/routers/accounts.py b/backend/api_service/app/routers/accounts.py
index 51baece..bcacb18 100644
--- a/backend/api_service/app/routers/accounts.py
+++ b/backend/api_service/app/routers/accounts.py
@@ -210,14 +210,18 @@ async def _verify_weibo_cookie(cookie_str: str) -> dict:
     Returns {"valid": bool, "uid": str|None, "screen_name": str|None}.
     """
     cookies = _parse_cookie_str(cookie_str)
-    async with httpx.AsyncClient(timeout=15, follow_redirects=True) as client:
-        # Step 1: check login via /ajax/side/cards
+    async with httpx.AsyncClient(timeout=15, follow_redirects=False) as client:
+        # Step 1: check login via /ajax/side/cards (不跟随重定向)
         resp = await client.get(
             "https://weibo.com/ajax/side/cards",
             params={"count": "1"},
-            headers=WEIBO_HEADERS,
+            headers={**WEIBO_HEADERS, "X-Requested-With": "XMLHttpRequest"},
             cookies=cookies,
         )
+
+        if resp.status_code in (301, 302):
+            return {"valid": False, "uid": None, "screen_name": None}
+
         try:
             data = resp.json()
         except Exception:
@@ -346,10 +350,9 @@ async def _get_super_topics(cookie_str: str, weibo_uid: str = "") -> List[dict]:
     cookies = _parse_cookie_str(cookie_str)
     topics: List[dict] = []
 
-    async with httpx.AsyncClient(timeout=15, follow_redirects=True) as client:
-        # First get XSRF-TOKEN by visiting weibo.com
-        await client.get("https://weibo.com/", headers=WEIBO_HEADERS, cookies=cookies)
-        xsrf = client.cookies.get("XSRF-TOKEN", "")
+    async with httpx.AsyncClient(timeout=15, follow_redirects=False) as client:
+        # 直接请求 API，不访问首页（避免 SSO 重定向）
+        xsrf = cookies.get("XSRF-TOKEN", "")
 
         headers = {
             **WEIBO_HEADERS,
@@ -414,10 +417,9 @@ async def _do_signin(cookie_str: str, topic_title: str, containerid: str) -> dic
     import time as _time
     cookies = _parse_cookie_str(cookie_str)
 
-    async with httpx.AsyncClient(timeout=15, follow_redirects=True) as client:
-        # Get XSRF-TOKEN
-        await client.get("https://weibo.com/", headers=WEIBO_HEADERS, cookies=cookies)
-        xsrf = client.cookies.get("XSRF-TOKEN", "")
+    async with httpx.AsyncClient(timeout=15, follow_redirects=False) as client:
+        # 直接从 Cookie 获取 XSRF，不访问首页
+        xsrf = cookies.get("XSRF-TOKEN", "")
 
         headers = {
             **WEIBO_HEADERS,
@@ -448,6 +450,10 @@ async def _do_signin(cookie_str: str, topic_title: str, containerid: str) -> dic
                 headers=headers,
                 cookies=cookies,
             )
+
+            if resp.status_code in (301, 302):
+                return {"status": "failed", "message": "签到API被重定向，Cookie可能失效"}
+
             try:
                 data = resp.json()
             except Exception:
diff --git a/backend/task_scheduler/app/main.py b/backend/task_scheduler/app/main.py
index 4d7b137..02afb34 100644
--- a/backend/task_scheduler/app/main.py
+++ b/backend/task_scheduler/app/main.py
@@ -411,7 +411,7 @@ async def _async_do_signin(account_id: str, cron_expr: str = ""):
         signed = already = failed = 0
         log_entries = []
 
-        async with httpx.AsyncClient(timeout=15, follow_redirects=True) as client:
+        async with httpx.AsyncClient(timeout=15, follow_redirects=False) as client:
             # 直接从 Cookie 获取 XSRF token，不访问首页
             xsrf = cookies.get("XSRF-TOKEN", "")
 
@@ -592,6 +592,11 @@ async def _do_single_signin(client, cookies: dict, topic: dict, xsrf: str) -> di
             },
             headers=h, cookies=cookies,
         )
+
+        # 被重定向 = Cookie 失效
+        if resp.status_code in (301, 302):
+            return {"status": "failed", "message": "签到API被重定向，Cookie可能失效"}
+
         try:
             data = resp.json()
         except Exception:
@@ -746,21 +751,23 @@ async def _build_daily_report() -> str:
                         remain_days = (expire_dt - now).days
                         expire_str = expire_dt.strftime("%m-%d")
 
-                    # 真实 API 验证
+                    # 真实 API 验证（不跟随重定向，直接请求 AJAX API）
                     real_valid = False
                     try:
-                        async with _httpx.AsyncClient(timeout=10, follow_redirects=True) as hc:
+                        async with _httpx.AsyncClient(timeout=10, follow_redirects=False) as hc:
                             vresp = await hc.get(
                                 "https://weibo.com/ajax/side/cards",
                                 params={"count": "1"},
-                                headers=WEIBO_HEADERS,
+                                headers={**WEIBO_HEADERS, "X-Requested-With": "XMLHttpRequest"},
                                 cookies=cookie_dict,
                             )
-                            try:
-                                vdata = vresp.json()
-                                real_valid = vdata.get("ok") == 1
-                            except Exception:
-                                real_valid = False
+                            if vresp.status_code == 200:
+                                try:
+                                    vdata = vresp.json()
+                                    real_valid = vdata.get("ok") == 1
+                                except Exception:
+                                    real_valid = False
+                            # 302 = Cookie 失效
                     except Exception:
                         real_valid = False