错误：任务执行失败'：app：transformClassesAndResourcesWithProguardForRelease'

Question

buildTypes {
    release {

        minifyEnabled true
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}

当我向我的应用发送proguard时我得到以下错误：

Error:Execution failed for task ':app:transformClassesAndResourcesWithProguardForRelease'