Stop jellyfin, try renaming /etc/jellyfin/system.xml and network.xml (add .orig to the name or something), start jellyfin. It will regenerate those files with defaults.
Jellyfin 10.10.7 (Docker)
Ubuntu 24.04.2 LTS w/HWE
Intel i3 12100
Intel Arc A380
OS drive - SK Hynix P41 1TB
Storage
4x WD Red Pro 6TB CMR in RAIDZ1