Unable to recognize JS server

Question

I was trying to setup react native for android. When I finally try to run the application, with react-native run-android, I get a message JS server not recognized, continuing with build.... The build is completed successfully and installed on the emulator. But since there is no JS server, I get the red screen that says Unable to download JS bundle.

Answer 1

This message means you have another service listening on port 8081, so the JS packager can't be started. You can find what process is blocking the port by running:

lsof -n -i4TCP:8081 | grep LISTEN

You can stop/kill this process and then run react-native run-android again.