Error: Debug variables info not available [closed]

Whenever I try to "debug" with Android Studio this error appears:

"debug variables info not available".

Code in gradle:

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
android {
    compileSdkVersion 27
    buildToolsVersion "26.0.2"
    defaultConfig {
        applicationId "br.com.appunivespcurso"
        minSdkVersion 23
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}


dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })

    compile "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
    //noinspection GradleCompatible
    compile 'com.android.support:support-compat:27.0.0'
    compile 'com.google.firebase:firebase-database:11.4.2'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    compile 'com.android.support:design:27.0.0'
    compile 'com.firebaseui:firebase-ui-database:3.1.0'
    compile 'com.android.support:recyclerview-v7:27.0.0'
    compile 'com.android.support:cardview-v7:27.0.0'
    testCompile 'junit:junit:4.12'
}

apply plugin: 'com.google.gms.google-services'
repositories {
    mavenCentral()
}