com.android.ddmlib.InstallException: Failed to establish session react-native

Question

I am trying to run react-native android app in my nexus5 emulator

adb devices
List of devices attached
emulator-5554   device

started pack

Answer 1

step :1 run(kill all adb)

 adb kill-server

step 2:list all connected devices(get your emulator id)

adb devices 

step 3:(replace ID to listed id from step2)

react-native run-android --deviceId ID

Note: make sure your previous app uninstalled in your emulator or physical device