FAILURE: Build failed with an exception.
No version of NDK matched the requested version 20.0.5594570. Versions available locally: 21.0.6113669

gradle版本：

classpath 'com.android.tools.build:gradle:3.6.0'

The three workarounds I know of are:

1. Install the older NDK it is looking for (side-by-side): sdkmanager 'ndk;20.0.5594570'
2. Manually specify the newer version in build.gradle:

   android {
       compileSdkVersion 29
       ndkVersion "21.0.6113669"
   
       //...
   }

3. Uninstall the NDK (if you don't need it for other projects): sdkmanager --uninstall 'ndk-bundle' This is essentially the same as deleting the NDK folder(s) as others have suggested in this thread.