As of now, VRChat uses a fork of yt-dlp 2026.02.04.
This issue in question is YouTube: Provider “deno” returned an invalid response · Issue #16118 · yt-dlp/yt-dlp & Request Format Not Available · Issue #16132 · yt-dlp/yt-dlp at upstream.
There is an unresolved issue at upstream (blocker) to reliably solve the issue: Recent players failing on all variants · Issue #51 · yt-dlp/ejs
Basically, it’s a waiting game right now for yt-dlp contributors to find a fix, release a new version, and then VRChat to patch their fork of yt-dlp with a new version.
I would’ve created a feature request for VRChat to update to yt-dlp 2026.03.03, but the fix in 2026.03.03 is a temporary bandaid fix at best and comes with its own bugs (#16128, #16131).
Follow this Canny topic for updates: Update yt-dlp to 2026.02.21 to resolve YouTube playback issues | Voters | VRChat