You can use either the feed URL (https://www.youtube.com/feeds/videos.xml?channel_id=UCQaB2gDCWpRsLqaDbilAyFQ) with RSS feed spout, or, preferably, the channel URL (https://www.youtube.com/channel/UCQaB2gDCWpRsLqaDbilAyFQ) with the YouTube spout.

Looking at the feed, the last video was published on 2025-10-05T08:29:11+00:00 and by default, items older than 30 days will not be kept.

You can verify by adding logger_level=DEBUG to your config. You should then see something like the following when updating:

item "More Flowers (Deleted Scene) | Aichaku/愛着 未公開映像" (2025-10-05T08:29:11+00:00) older than 30 days

You can increase the items_lifetime or if using selfoss ≥ 2.20) set it to 0 to keep older items. Though this will be at the cost of database size.

Vincèn