"No resource found that matches the given name" in values.xml

I made some changes to build.gradle of the application, and I think this caused a resource error, which I still have not found a solution for.

build.gradle:

applyplugin:'com.android.application'android{compileSdkVersion27buildToolsVersion"27.0.1"
    defaultConfig {
        applicationId 'com.app.user'
        minSdkVersion 15
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    productFlavors {
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.mercadopago:sdk:3.8.0'
    compile 'com.android.support:appcompat-v7:27.0.0'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    compile 'com.google.firebase:firebase-database:9.6.1'
    compile 'com.google.firebase:firebase-core:9.6.1'
    compile 'com.google.firebase:firebase-storage:9.6.1'
    compile 'com.google.firebase:firebase-auth:9.6.1'
    compile 'com.squareup.picasso:picasso:2.5.2'
    compile 'com.android.support:design:27.0.0'
    compile 'com.mikhaellopez:circularimageview:3.0.2'
    compile 'com.google.android.gms:play-services-auth:9.6.1'
    compile 'com.joooonho:selectableroundedimageview:1.0.1'
    testCompile 'junit:junit:4.12'
}








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

Code with error, in values.xml

I tried to change the version of the SDK, but it did not work.