React Native Task :app:validateSigningDebug FAILED

The problem is that the build is looking for the debug keystore and cannot find it.

Keystore file /home/tawsif/react native/react-native-redux/android/app/debug.keystore not found for signing config 'debug'.

There's an issue with the same problem in React Native GitHub. According to the page, you can solve it by creating a debug keystore. Quote from the thread:

You can generate the debug keystore by running this command in the android/app/ directory: keytool -genkey -v -keystore debug.keystore -storepass android -alias androiddebugkey -keypass android -keyalg RSA -keysize 2048 -validity 10000

Link to the issue: https://github.com/facebook/react-native/issues/25629

Just download from official template https://raw.githubusercontent.com/facebook/react-native/master/template/android/app/debug.keystore

Copy debug.keystore into your android/app/.

Ex: mv ~/Downloads/debug.keystore /Users/lazaro/apps/myapp/android/app/

ref: https://github.com/facebook/react-native/issues/25629#issuecomment-513245590

Based on @rabbit87's answer the solution is running the following command inside ProjectName/Andoid/app directory solves the problem

keytool -genkey -v -keystore debug.keystore -storepass android -alias androiddebugkey -keypass android -keyalg RSA -keysize 2048 -validity 10000