signed apk Crashes on startup in the real device

Question

i have generated the apk of my flutter application and now when i installed this apk on real device it crashes in the start is there any way to find the problem or any way to resolve this problem ?

    defaultConfig {
        (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.XXXXX.XXXXX"
        minSdkVersion 19
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        multiDexEnabled true
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    signingConfigs {
        release {
            keyAlias keystoreProperties['keyAlias']
            keyPassword keystoreProperties['keyPassword']
            storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
            storePassword keystoreProperties['storePassword']
        }
    }
    buildTypes {
        release {
            shrinkResources true
            minifyEnabled true
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.release
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation fileTree(dir: 'libs', include: '*.jar')
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
    api 'com.google.firebase:firebase-core:16.0.1'
    api 'com.google.firebase:firebase-auth:19.2.0'
    api 'com.google.firebase:firebase-ads:16.0.1'


}
apply plugin: 'com.google.gms.google-services'