CHECK YOUR ANTI-VIRUS FIREWALL SETTINGS.
I have a NodeJS server working on Windows 10 PC, but when I put the IP address and port (example http://102.168.1.123:5000) into another computer's browser on my local network nothing happened, although it worked OK on the host computer.
(To find your windows IP address run CMD, then IPCONFIG)
Bar Horing Amir's answer points to the Windows firewall settings. On My PC the Windows Firewall was turned off - as McAfee anti-virus has added its own Firewall.
My system started to work on other computers after I added port 5000 to 'Ports and Systems Services' under the McAfee Firewall settings on the computer with NodeJS on it. Other anti-virus software will have similar settings.
I would seriously suggest trying this solution first with Windows.