diff --git a/youtube_dlc/extractor/youtube.py b/youtube_dlc/extractor/youtube.py
index d3ba4c73c..295e9f770 100644
--- a/youtube_dlc/extractor/youtube.py
+++ b/youtube_dlc/extractor/youtube.py
@@ -549,7 +549,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
         '396': {'acodec': 'none', 'vcodec': 'av01.0.05M.08'},
         '397': {'acodec': 'none', 'vcodec': 'av01.0.05M.08'},
     }
-    _SUBTITLE_FORMATS = ('srv1', 'srv2', 'srv3', 'ttml', 'vtt', 'json3')
+    _SUBTITLE_FORMATS = ('srv1', 'srv2', 'srv3', 'ttml', 'vtt') # 'json3'
 
     _GEO_BYPASS = False