Failed to resolve: com.android.support:appcompat-v7:25.1.0

Make sure that the repositories section includes a maven section with the “https://maven.google.com” endpoint. For example:

allprojects {
    repositories {
        jcenter()
        maven {
            url "https://maven.google.com"
        }
    }
}

Update:

allprojects {
    repositories {
        google()

        // If you're using a version of Gradle lower than 4.1, you must
        // instead use:
        //
        // maven {
        //     url 'https://maven.google.com'
        // }
    }
}

See android documention for details