diff --git a/backend/routers/channels.py b/backend/routers/channels.py
index 65d0de1..18362fd 100644
--- a/backend/routers/channels.py
+++ b/backend/routers/channels.py
@@ -1185,7 +1185,7 @@ def follow_by_url(
 
     channel = db.query(Channel).filter_by(youtube_channel_id=yt_channel_id).first()
     if not channel:
-        meta = ytdlp.fetch_channel_metadata(yt_channel_id, max_videos=30)
+        meta = ytdlp.fetch_channel_metadata(yt_channel_id, max_videos=30, polite=True)
         if not meta or not meta.get("channel"):
             raise HTTPException(status_code=404, detail="Channel not found on YouTube")
         ch_data = meta["channel"]
diff --git a/backend/routers/downloads.py b/backend/routers/downloads.py
index 3615428..3dcbe2b 100644
--- a/backend/routers/downloads.py
+++ b/backend/routers/downloads.py
@@ -125,7 +125,7 @@ def _ensure_video(db: Session, youtube_video_id: str) -> Video:
     if video:
         return video
 
-    meta = ytdlp.fetch_video_metadata(youtube_video_id)
+    meta = ytdlp.fetch_video_metadata(youtube_video_id, polite=True)
     if not meta:
         raise HTTPException(status_code=404, detail="Video not found on YouTube")
 
diff --git a/backend/routers/search.py b/backend/routers/search.py
index 3fb0e3b..4c1723c 100644
--- a/backend/routers/search.py
+++ b/backend/routers/search.py
@@ -264,8 +264,9 @@ def search(
 
     source = "local" if (video_results or channel_results) else "none"
 
-    # Fall back to live yt-dlp search if no local results or explicitly requested
-    if not video_results or live:
+    # Fall back to live yt-dlp search if no local results or explicitly requested.
+    # Skip if a download is active — concurrent yt-dlp sessions invalidate cookies.
+    if (not video_results or live) and not ytdlp.is_download_active():
         try:
             live_raw = ytdlp.search_youtube(q)
             live_results = _live_search_to_results(db, current_user.id, live_raw)
diff --git a/backend/services/ytdlp.py b/backend/services/ytdlp.py
index 90e3320..7679881 100644
--- a/backend/services/ytdlp.py
+++ b/backend/services/ytdlp.py
@@ -84,6 +84,11 @@ def _meta_run(args: list[str], timeout: int = 60) -> tuple[str, str, int]:
             _meta_last_call = time.monotonic()
 
 
+def is_download_active() -> bool:
+    with _active_downloads_lock:
+        return _active_downloads > 0
+
+
 def _parse_date(date_str: str | None) -> datetime | None:
     if not date_str:
         return None