diff --git a/yt_dlp/extractor/niconico.py b/yt_dlp/extractor/niconico.py
index b0885d34f..7a0628b4b 100644
--- a/yt_dlp/extractor/niconico.py
+++ b/yt_dlp/extractor/niconico.py
@@ -794,11 +794,7 @@ def _real_extract(self, url):
             {extract_attributes}, 'data-props', {json.loads}))
         frontend_id = traverse_obj(embedded_data, ('site', 'frontendId', {str_or_none}), default='9')
 
-        if not (ws_url := traverse_obj(embedded_data, (
-            'site', 'relive', 'webSocketUrl', {url_or_none},
-        ))):
-            raise ExtractorError('Unable to fetch WebSocket URL', expected=True)
-
+        ws_url = traverse_obj(embedded_data, ('site', 'relive', 'webSocketUrl', {url_or_none}, {require('websocket URL')}))
         ws_url = update_url_query(ws_url, {'frontend_id': frontend_id})
         ws = self._request_webpage(
             ws_url, video_id, 'Connecting to WebSocket server',