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

Code:
server {

      server_name my_domain;



      access_log /var/log/nginx/jellyfin.access;

      error_log /var/log/nginx/jellyfin.error;



      set $jellyfin 127.0.0.1;



      location / {

          proxy_pass http://127.0.0.1:8096;

          proxy_set_header Host $host;

          proxy_set_header X-Real-IP $remote_addr;



          proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

          proxy_set_header X-Forwarded-Proto $scheme;

          proxy_set_header X-Forwarded-Protocol $scheme;

          proxy_set_header X-Forwarded-Host $http_host;



          # Disable buffering when the nginx proxy gets very resource heavy upon streaming

          proxy_buffering off;

      }



      location /socket {

          # Proxy Jellyfin Websockets traffic

          proxy_pass http://$127.0.0.1:8096;

          proxy_http_version 1.1;

          proxy_set_header Upgrade $http_upgrade;

          proxy_set_header Connection "upgrade";

          proxy_set_header Host $host;

          proxy_set_header X-Real-IP $remote_addr;

          proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

          proxy_set_header X-Forwarded-Proto $scheme;

          proxy_set_header X-Forwarded-Protocol $scheme;

          proxy_set_header X-Forwarded-Host $http_host;

      }



        # Security / XSS Mitigation Headers

        #add_header X-Frame-Options "SAMEORIGIN";

        add_header Cross-Origin-Resource-Policy "cross-origin" always;

        add_header X-XSS-Protection "1; mode=block";

        add_header X-Content-Type-Options "nosniff";



    listen 443 ssl; # managed by Certbot

    ssl_certificate /etc/letsencrypt/live/my_domain/fullchain.pem; # managed by Certbot

    ssl_certificate_key /etc/letsencrypt/live/my_domain/privkey.pem; # managed by Certbot

    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot

    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot



}

server {

    if ($host = my_domain) {

        return 301 https://$host$request_uri;

    } # managed by Certbot





      listen 80;

      server_name my_domain;

    return 404; # managed by Certbot





}