Android Studio desplay this Error "ASCII Open File"

apply plugin: 'com.android.application'
android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.burhanuday.wordpressblog"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    implementation 'com.android.support:recyclerview-v7:28.0.0'
    implementation 'io.reactivex.rxjava2:rxjava:2.1.9'
    implementation 'io.reactivex.rxjava2:rxandroid:2.0.1'
    implementation "com.jakewharton:butterknife:8.8.1"
    annotationProcessor "com.jakewharton:butterknife-compiler:8.8.1"
    implementation "com.squareup.retrofit2:retrofit:2.4.0"
    implementation "com.squareup.retrofit2:converter-gson:2.4.0"
    implementation "com.jakewharton.retrofit:retrofit2-rxjava2-adapter:1.0.0"
    implementation "com.squareup.okhttp3:okhttp:3.10.0"
    implementation "com.squareup.okhttp3:okhttp-urlconnection:3.0.1"
    implementation 'com.asksira.android:webviewsuite:1.0.3'
    implementation 'com.android.support:customtabs:28.0.0'
    implementation 'com.firebase:firebase-jobdispatcher:0.8.5'
}