To fix that, you have to open the SDK Manager, deselect the ‘Hide obsolete packages’ option on the bottom-right corner, and further, install the Android SDK Tools (obsolete) folder.

You’ll find this in Android Studio if you navigate to Tools — Android — SDK Manager. You’ll see there are three tabs here for SDK Platforms, SDK Tools, and SDK Update Sites.

Android development starts with the Android SDK - a collection of tools needed to build any kind of Android app. Discover what's included and how to use it.