Failed to resolve: com.android.support:appcompat-v4:23.0.0

I'm using Android Studio version 3, the cell that I try uses the api 23, so I tried to change the gradle, but I get the error message Failed to resolve: com.android.support:appcompat-v4:23.0.0

apply plugin: 'com.android.application'

android {
compileSdkVersion 23
defaultConfig {
    applicationId "com.example.jhon.edittextvalidation2"
    minSdkVersion 23
    targetSdkVersion 23
    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-v4:23.0.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}