The Flutter error requires Android SDK 28 and the Android BuildTools 28.0.3

1- Android SDK version 28

Android Platforms TAB -> SDK Manager -> SDK Platforms TAB -> Select Android 9.0 Pie and install

2- Android BuildTools version 28.0.3

Android Studio -> SDK Manager -> SDK Tools TAB -> select the lower right corner Show Package Details -> Android SDK build-Tools select 28.0.3 and download

Then restart Android Studio and enter the command in CMD