Useful or not, from you.
react-native Unknown failure cmd: Can't find service: package

Task :app:installDebug 09:08:07 V/ddms: execute: running am get-config 09:08:07 V/ddms: execute 'am get-config' on 'emulator-5554' : EOF hit. Read: -1 09:08:07 V/ddms: execute: returning Installing APK 'app-debug.apk' on 'Nexus_5X_API_28_x86(AVD) - 9' for app:debug 09:08:07 D/app-debug.apk: Uploading app-debug.apk onto device 'emulator-5554' 09:08:07 D/Device: Uploading file onto device 'emulator-5554' 09:08:07 D/ddms: Reading file permision of D:\react-native\Kemenkop\android\app\build\outputs\apk\debug\app-debug.apk as: rwx------ 09:08:08 V/ddms: execute: running pm install -r -t "/data/local/tmp/app-debug.apk" 09:08:08 V/ddms: execute 'pm install -r -t "/data/local/tmp/app-debug.apk"' on 'emulator-5554' : EOF hit. Read: -1 09:08:08 V/ddms: execute: returning Unable to install D:\react-native\Kemenkop\android\app\build\outputs\apk\debug\app-debug.apk com.android.ddmlib.InstallException: Unknown failure (cmd: Can't find service: package) . . . Task :app:installDebug FAILED

FAILURE: Build failed with an exception.

  • What went wrong: Execution failed for task ':app:installDebug'.

com.android.builder.testing.api.DeviceException: com.android.ddmlib.InstallException: Unknown failure (cmd: Can't find service: package)

  • Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

  • Get more help at https://help.gradle.org

BUILD FAILED in 1m 1s 62 actionable tasks: 1 executed, 61 up-to-date Could not install the app on the device, read the error above for details. Make sure you have an Android emulator running or a device connected and have set up your Android development environment: https://facebook.github.io/react-native/docs/getting-started.html

Command failed: gradlew.bat installDebug

Error: Command failed: gradlew.bat installDebug at checkExecSyncError (child_process.js:637:11) at Object.execFileSync (child_process.js:655:13) at runOnAllDevices (D:\react-native\Kemenkop\node_modules\react-native\local-cli\runAndroid\runAndroid.js:299:19) at buildAndRun (D:\react-native\Kemenkop\node_modules\react-native\local-cli\runAndroid\runAndroid.js:135:12) at isPackagerRunning.then.result (D:\react-native\Kemenkop\node_modules\react-native\local-cli\runAndroid\runAndroid.js:65:12) at processTicksAndRejections (internal/process/task_queues.js:86:5)

That's a useful answer
Without any help

I just ran into the same error. In my case the emulator was frozen. I had to go to AVD Manager in Android Studio and run "Cold Boot Now" on the specific emulator to get it back up, then this error went away.