diff --git a/app.py b/app.py
index 5f37a8c..b6bf674 100644
--- a/app.py
+++ b/app.py
@@ -260,6 +260,11 @@ def proxy(video_id):
     # Not in cache or cache expired; fetch from nicovideo.jp
     real_url = f"https://www.nicovideo.jp/watch/{video_id}"
     params, soup = get_data(video_id, real_url)
+
+    if not params and not soup:
+        logger.error(f"Failed to retrieve data for video ID '{video_id}'")
+        return Response("Video not found", status=404)
+
     thumbnail_url = (
         params["video"]["thumbnail"].get("ogp") or
         params["video"]["thumbnail"].get("player") or
@@ -282,7 +287,7 @@ def proxy(video_id):
                     logger.info(f"Queued video ID {video_id} for download")
 
     cdn_video_url = get_cdn_url(video_id)
-    og_tags = soup.find_all("meta", property=lambda x: x)  # type: ignore
+    og_tags = soup.find_all("meta", property=lambda x: x)
     og_video_width = None
     og_video_height = None
     for tag in og_tags: