This assumes that Jellyfin is installed int the defalut location.
Open PowerShell as an Administrator then run:
- Activate firewall and set defaults
Set-NetFirewallProfile -Profile Domain,Public,Private -Enabled True
Set-NetFirewallProfile -DefaultInboundAction Block -DefaultOutboundAction Allow –NotifyOnListen True -AllowUnicastResponseToMulticast True –LogFileName %SystemRoot%\System32\LogFiles\Firewall\pfirewall.log