HLS Playback Troubleshooting: Complete Checklist from CORS to 403
Published：2026-02-04 · Read 12 min
A practical checklist to locate HLS playback failures from URL validity to auth and segment health.
Validate the playlist first
Open the URL directly and ensure it returns a valid playlist with #EXTM3U.
If the URL redirects to login or returns HTML, playback will fail before segment loading.
Separate CORS from auth failures
CORS issues are browser-side blocking problems, while 401/403 are authorization problems.
Fix CORS with response headers and fix auth with token/signature strategy.