SOLVED: Jellyfin does not trancscode 4K HEVC in web player

[TheDreadPirate]

For testing, can you set X-XSS-Protection from "1; mode=block" to "0". Our documentation says to not enable it, period.

Code:

# Security / XSS Mitigation Headers
    # NOTE: X-Frame-Options may cause issues with the webOS app
    add_header X-XSS-Protection "0"; # Do NOT enable. This is obsolete/dangerous
    add_header X-Content-Type-Options "nosniff";

Reload nginx and try again.