Unable to reach server via local IP, only "localhost" For years I've been able to use my local IP to access local servers during development.  e.g. http://192.168.80.20:3000. It seems that after updating to macOS 10.15.4 this is no longer possible.  I can only access my projects with localhost e.g. http://localhost:3000. This is fine for when I am using a local client such as Chrome or iOS Simulator, but I also need to do testing across my local network from another device.  I'm not sure what changed!
Make sure NodeJS is listening on all interfaces.


:3000
localhost:3000
[::]:3000 
127.0.0.1:3000


All the above are different but all are listening on port 3000. Only the first :3000 listens to every interface: IPv4, IPv6, and other interfaces like ethernet and WiFi.

Use sudo lsof -i show which ports, interfaces, and protocols your server is listening to.