In that case, uninstall the SDK and install an earlier version. There might be cases in which Google has released a new version of the SDK that causes errors when you build your Unity Project.
When installing the Android platform SDK and other tools, you can typically install the latest available version. If you encounter errors, Unity recommends using the command line method. Note: Android Studio provides some ease of use benefits, but it is not fully tested for compatibility with Unity installs. The Android developer portal provides detailed installation instructions. Install Android studio from the Android developer portal. Sdkmanager “extras google usb_driver” 1b.
After installing, open the Android SDK Manager and add at least one Android SDK Platform, the Platform Tools, the Build Tools, and the USB drivers if you’re using Windows. Install the Android SDK using the command line tools Using the command line tools is a smaller download and does not install additional software, but it can be more challenging to use. Android Studio provides an easy to use GUI based tool but installs additional software on your computer. You can install the Android SDK using command line tools or through Android Studio. By default, Unity installs a Java Development Kit based on OpenJDK. More info See in Glossary, you must also install the Android Native Development Kit (NDK). Universal Windows Platform, however, supports only two. Unity supports three different scripting backends depending on target platform: Mono. If you want to use the IL2CPP scripting backend A framework that powers scripting in Unity. You also need to install the Android Software Development Kit (SDK) to build and run any code on your Android device. To build and run for Android, you must install the Unity Android Build Support platform module.