diff --git a/backend/config_parser.py b/backend/config_parser.py
index 0b35559..1e39752 100644
--- a/backend/config_parser.py
+++ b/backend/config_parser.py
@@ -294,12 +294,18 @@ class TranscodeTools:
             raise NeedNVR
 
         if not os.path.exists(raw_file) or os.path.getsize(raw_file) == 0:
-            self.logger.info(f"download new preview {preview_file}")
-            async with aiofiles.open(raw_file, "wb") as raw:
-                async for chunk in nvr.stream_file(file, preview_pre_bytes):
-                    await raw.write(chunk)
+            try:
+                async with asyncio.timeout(10):
+                    self.logger.info(f"download new preview {preview_file}")
+                    async with aiofiles.open(raw_file, "wb") as raw:
+                        async for chunk in nvr.stream_file(file, preview_pre_bytes):
+                            await raw.write(chunk)
+            except asyncio.TimeoutError as te:
+                self.logger.info(f"Cancel download file: {te}")
+                os.remove(raw_file)
+            finally:
+                nvr.logout()
 
-        nvr.logout()
         raw_file_avi = await self.h264toavi(raw_file)
         if self.delete_temporary_files:
             self.deleteFile(raw_file)
diff --git a/backend/nvr_core.py b/backend/nvr_core.py
index 6b0d1b3..748618e 100644
--- a/backend/nvr_core.py
+++ b/backend/nvr_core.py
@@ -30,8 +30,11 @@ class NVR:
         await self.client.login(self.loop)
 
     def logout(self):
-        self.logger.debug(f"[{self.index}] Logout to {self.client}")
-        self.client.close()
+        try:
+            self.logger.debug(f"[{self.index}] Logout to {self.client}")
+            self.client.close()
+        except:
+            pass
 
     async def channels(self):
         self.logger.debug(f"[{self.index}] Get channels")
diff --git a/backend/server.py b/backend/server.py
index 6e557cc..c8a5d0c 100644
--- a/backend/server.py
+++ b/backend/server.py
@@ -1,3 +1,5 @@
+import asyncio
+
 from fastapi import FastAPI, Response, BackgroundTasks, Header, Request
 from fastapi.responses import StreamingResponse, FileResponse
 from fastapi.security import HTTPBasic, HTTPBasicCredentials
@@ -247,7 +249,7 @@ class Server:
                     headers.update({"Content-Length":str(os.path.getsize(preview))})
                     headers.update({"Content-Disposition": f'attachment; filename="preview.webp"'})
                     return FileResponse(preview, media_type="application/octet-stream", headers=headers)
-                except NeedNVR:
+                except NeedNVR | FileNotFoundError:
                     background_tasks.add_task(loadPreview, file = file)
                     return FileResponse("./assets/loading.webp")