Your ROOT_URL in app.ini is https://git.cloudchain.link/ but you are visiting https://dash.bss.nz/open-source-mirrors/jellyfin/blame/commit/1c5c0ebb0fd7d3845d81d3731f86c5ff4c06641d/debian/jellyfin.service
You should set ROOT_URL correctly, otherwise the web may not work correctly.
[Unit]
Description = Jellyfin Media Server
After = network-online.target
[Service]
Type = simple
EnvironmentFile = /etc/default/jellyfin
User = jellyfin
ExecStart = /usr/bin/jellyfin ${JELLYFIN_WEB_OPT} ${JELLYFIN_RESTART_OPT} ${JELLYFIN_FFMPEG_OPT} ${JELLYFIN_SERVICE_OPT} ${JELLYFIN_NOWEBAPP_OPT} ${JELLYFIN_ADDITIONAL_OPTS}
Restart = on-failure
TimeoutSec = 15
NoNewPrivileges = true
SystemCallArchitectures = native
RestrictAddressFamilies = AF_UNIX AF_INET AF_INET6 AF_NETLINK
RestrictNamespaces = true
RestrictRealtime = true
RestrictSUIDSGID = true
ProtectControlGroups = true
ProtectHostname = true
ProtectKernelLogs = true
ProtectKernelModules = true
ProtectKernelTunables = true
LockPersonality = true
PrivateTmp = true
PrivateDevices = false
PrivateUsers = true
RemoveIPC = true
SystemCallFilter = ~@clock
SystemCallFilter = ~@aio
SystemCallFilter = ~@chown
SystemCallFilter = ~@cpu-emulation
SystemCallFilter = ~@debug
SystemCallFilter = ~@keyring
SystemCallFilter = ~@memlock
SystemCallFilter = ~@module
SystemCallFilter = ~@mount
SystemCallFilter = ~@obsolete
SystemCallFilter = ~@privileged
SystemCallFilter = ~@raw-io
SystemCallFilter = ~@reboot
SystemCallFilter = ~@setuid
SystemCallFilter = ~@swap
SystemCallErrorNumber = EPERM
[Install]
WantedBy = multi-user.target