gradle project sync failed 질문

Question

현재 설정된 버전인데 자꾸 제목과같은 오류가 뜨는데 해결방법이 없을까요??

build.gradle(Module:demo)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 27

    defaultConfig {
        applicationId "com.android.tonyvu.sc.demo"
        minSdkVersion 19
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:27.1.1'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test.ruuner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso-core:3.0.2'
    compile project(path: ':library')
}

 

build.gradle(Module:library)

apply plugin: 'com.android.library'

android {
    compileSdkVersion 27
    buildToolsVersion "27.0.1"

    defaultConfig {
        minSdkVersion 8
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}