Error:

* What went wrong:
Execution failed for task ‘:app:stripDebugDebugSymbols’.
> No version of NDK matched the requested version 21.0.6113669. Versions available locally: 21.4.7075529

Solution:

To solve the above issue in Android, just ndkVersion “21.4.7075529” to app/build.gradle file inside android block.

Example:

android {
 ndkVersion "21.4.7075529"
}