diff --git a/common/lib/xmodule/xmodule/video_module/video_handlers.py b/common/lib/xmodule/xmodule/video_module/video_handlers.py
index 9e9db860ca..d785edec5b 100644
--- a/common/lib/xmodule/xmodule/video_module/video_handlers.py
+++ b/common/lib/xmodule/xmodule/video_module/video_handlers.py
@@ -104,6 +104,7 @@ class VideoStudentViewHandlers(object):
 
         Raises:
             NotFoundError if for 'en' subtitles no asset is uploaded.
+            NotFoundError if youtube_id does not exist / invalid youtube_id
         """
         if youtube_id:
             # Youtube case:
@@ -111,7 +112,9 @@ class VideoStudentViewHandlers(object):
                 return Transcript.asset(self.location, youtube_id).data
 
             youtube_ids = youtube_speed_dict(self)
-            assert youtube_id in youtube_ids
+            if youtube_id not in youtube_ids:
+                log.info("Youtube_id %s does not exist", youtube_id)
+                raise NotFoundError
 
             try:
                 sjson_transcript = Transcript.asset(self.location, youtube_id, self.transcript_language).data
diff --git a/lms/djangoapps/courseware/tests/test_video_handlers.py b/lms/djangoapps/courseware/tests/test_video_handlers.py
index 0bf1dad60e..4d80952848 100644
--- a/lms/djangoapps/courseware/tests/test_video_handlers.py
+++ b/lms/djangoapps/courseware/tests/test_video_handlers.py
@@ -322,6 +322,11 @@ class TestTranscriptTranslationGetDispatch(TestVideo):
         response = self.item.transcript(request=request, dispatch='translation/ru')
         self.assertEqual(response.status, '404 Not Found')
 
+        # Youtube_id is invalid or does not exist
+        request = Request.blank('/translation/uk?videoId=9855256955511225')
+        response = self.item.transcript(request=request, dispatch='translation/uk')
+        self.assertEqual(response.status, '404 Not Found')
+
     def test_translaton_en_youtube_success(self):
         subs = {"start": [10], "end": [100], "text": ["Hi, welcome to Edx."]}
         good_sjson = _create_file(json.dumps(subs))