diff --git a/src/app/services/fl_downloader.py b/src/app/services/fl_downloader.py
index 4c8acd4..cbc5b38 100644
--- a/src/app/services/fl_downloader.py
+++ b/src/app/services/fl_downloader.py
@@ -153,9 +153,12 @@ class FLDownloader(BaseDownloader):
 
             await temp_file.flush()
 
-            return await asyncio.get_event_loop().run_in_executor(
-                process_pool_executor, unzip, temp_file.name, "fb2"
-            )
+            try:
+                return await asyncio.get_event_loop().run_in_executor(
+                    process_pool_executor, unzip, temp_file.name, "fb2"
+                )
+            except FileNotFoundError:
+                return None
 
     async def _download_with_converting(
         self,
@@ -185,6 +188,9 @@ class FLDownloader(BaseDownloader):
             await response.aclose()
             await client.aclose()
 
+        if filename_to_convert is None:
+            raise ValueError
+
         form = {"format": self.file_type}
         files = {"file": open(filename_to_convert, "rb")}
 
@@ -241,6 +247,9 @@ class FLDownloader(BaseDownloader):
             await response.aclose()
             await client.aclose()
 
+        if temp_filename is None:
+            return None
+
         if self.need_zip:
             content_filename = await asyncio.get_event_loop().run_in_executor(
                 process_pool_executor, zip, await self.get_filename(), temp_filename