diff --git a/ChinaXivXiv/mongo_ops.py b/ChinaXivXiv/mongo_ops.py
index d02c033..6dd1c44 100644
--- a/ChinaXivXiv/mongo_ops.py
+++ b/ChinaXivXiv/mongo_ops.py
@@ -53,8 +53,8 @@ async def claim_task(queue: motor.motor_asyncio.AsyncIOMotorCollection,
     )
     return Task(**TASK) if TASK else None
 
-async def update_task(queue: motor.motor_asyncio.AsyncIOMotorCollection, TASK: Task, status: str):
-    assert status in Status.__dict__.values()
+async def update_task(queue: motor.motor_asyncio.AsyncIOMotorCollection, TASK: Task, status: str|int):
+    # assert status in Status.__dict__.values()
     update = {"$set": {
             "status": status,
         }}
diff --git a/ChinaXivXiv/workers/IA_uploader.py b/ChinaXivXiv/workers/IA_uploader.py
index 3349011..4cc2d5c 100644
--- a/ChinaXivXiv/workers/IA_uploader.py
+++ b/ChinaXivXiv/workers/IA_uploader.py
@@ -68,6 +68,10 @@ async def IA_upload_worker(client: httpx.AsyncClient, collection: motor.motor_as
             'Connection': 'close', # 对面服务器有点奇葩，HEAD 不会关闭连接……
         }
         r_html = await client.get(chinaxiv_permanent_with_version_url, headers=headers, follow_redirects=False)
+        if r_html.status_code == 404:
+            print(f"404, skipping {chinaxiv_permanent_with_version_url}")
+            await update_task(collection, TASK, status=404)
+            continue
         assert r_html.status_code == 200
 
         html_metadata = get_chinaxivhtmlmetadata_from_html(html=r_html.content, url=chinaxiv_permanent_with_version_url)