I want to download Build Tools version 26.0.2 but it will not let me download it because of my geographical position (I'm in Cuba) in the SDK Manager.
I imagine you are in Cuba, in this case you must configure your Android Studio to work offline, you must not allow Android Studio to have internet connection, enter the
Settings ( Ctrl + < kbd> Alt + s
You must configure it to use a local distribution of Gradle.
This article in Spanish is excellent: