Firebase crashlytics doesn't work for Android

I have integrated firebase analytics and crashlytics into react-native application.The analytics part works fine.

But Crashlytics doesn't work for android, see attachment below.

For IOS at least it shows something on firebase console.

Here is what I see in adb logcat for android.

Caused by: java.lang.RuntimeException: Background thread crash
01-06 14:21:47.949 15169 20465 E AndroidRuntime:    at com.crashlytics.android.core.CrashTest.throwRuntimeException(CrashTest.java:21)
01-06 14:21:47.949 15169 20465 E AndroidRuntime:    at com.crashlytics.android.core.CrashTest$1.doInBackground(CrashTest.java:50)
01-06 14:21:47.949 15169 20465 E AndroidRuntime:    at com.crashlytics.android.core.CrashTest$1.doInBackground(CrashTest.java:42)
01-06 14:21:47.949 15169 20465 E AndroidRuntime:    at android.os.AsyncTask$3.call(AsyncTask.java:378)
01-06 14:21:47.949 15169 20465 E AndroidRuntime:    at java.util.concurrent.FutureTask.run(FutureTask.java:266)

I have tried every other solution on stackoverflow but didn't help

android/app/build.gradle

apply plugin: "com.android.application"
apply plugin: "io.fabric"


import com.android.build.OutputFile
project.ext.react = [
        entryFile: "index.js"
]

apply from: "../../node_modules/react-native/react.gradle"
apply from: "../../node_modules/react-native-vector-icons/fonts.gradle"
def enableSeparateBuildPerCPUArchitecture = false
def enableProguardInReleaseBuilds = false
android {
    compileSdkVersion rootProject.ext.compileSdkVersion
    buildToolsVersion rootProject.ext.buildToolsVersion

    defaultConfig {
        applicationId "*.*.*"
        minSdkVersion rootProject.ext.minSdkVersion
        targetSdkVersion rootProject.ext.targetSdkVersion
        versionCode 48
        versionName "6.3.15"
        multiDexEnabled true
        ndk {
            abiFilters 'armeabi-v7a','arm64-v8a','x86','x86_64'
        }
        lintOptions {
            checkReleaseBuilds false
            abortOnError false
        }
        missingDimensionStrategy 'react-native-camera', 'general'

    }
    compileOptions {
        sourceCompatibility 1.8
        targetCompatibility 1.8
    }
    splits {
        abi {
            reset()
            enable enableSeparateBuildPerCPUArchitecture
            universalApk false  // If true, also generate a universal APK
            include 'armeabi-v7a','arm64-v8a','x86','x86_64'
        }
    }
    buildTypes {
        release {
            minifyEnabled enableProguardInReleaseBuilds
            proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
        }
    }
    // applicationVariants are e.g. debug, release
    applicationVariants.all { variant ->
        variant.outputs.each { output ->
            // For each separate APK per architecture, set a unique version code as described here:
            // http://tools.android.com/tech-docs/new-build-system/user-guide/apk-splits
            def versionCodes = ["armeabi-v7a":1, "x86":2, "arm64-v8a": 3, "x86_64": 4]
            def abi = output.getFilter(OutputFile.ABI)
            if (abi != null) {  // null for the universal-debug, universal-release variants
                output.versionCodeOverride =
                        versionCodes.get(abi) * 1048576 + defaultConfig.versionCode
            }
        }
    }
}

dependencies {
    implementation project(':@react-native-firebase_crashlytics')
    implementation project(':@react-native-firebase_app')
    implementation project(':@react-native-firebase_analytics')
    implementation project(':react-native-network-info')
    implementation project(':react-native-camera')    
    implementation project(':trace-network')
    implementation project(':react-native-wmsso')
    implementation project(':rn-fetch-blob')
    implementation project(':react-native-webview')
    implementation project(':react-native-video')
    implementation project(':react-native-haptic-feedback')
    implementation project(':react-native-gesture-handler')
    implementation project(':react-native-device-info')
    implementation fileTree(dir: "libs", include: ["*.jar"])
    implementation "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"
    implementation "com.facebook.react:react-native:+"  
}
buildscript {
    repositories {
        google()
        maven {
            url 'https://maven.google.com'
        }
        maven { url 'https://maven.fabric.io/public' }
        jcenter()




    dependencies {

        classpath 'com.google.gms:google-services:4.2.0'

    }


}



task copyDownloadableDepsToLibs(type: Copy) {
    from configurations.compile
    into 'libs'
}



buildscript {
    repositories {
        mavenCentral()
        jcenter()
    }

}


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

android/build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    ext {
        buildToolsVersion = "28.0.3"
        minSdkVersion = 19
        compileSdkVersion = 28
        targetSdkVersion = 28
        supportLibVersion = "28.0.0"
    }
    repositories {
        google()
        jcenter()

        maven { url 'https://maven.fabric.io/public' }

    dependencies {
        classpath("com.android.tools.build:gradle:3.4.0")
        classpath 'com.google.gms:google-services:4.3.3'
        classpath 'io.fabric.tools:gradle:1.31.2'
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        mavenCentral()
        maven {
            url 'https://maven.google.com'
        }

        maven {
            // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
            url "$rootDir/../node_modules/react-native/android"
        }
    }
}