Hi edy,
This is usually caused by a combination of the version of Gradle you are building your app against and/or the version of Gradle expected by the version of WM you are using. You're not giving us much to go on in your post, but your error is usually caused by a new restriction in Android 9.
Just guessing, but have you skipped upgrading Gradle or maybe manually installed a new or different version of Gradle?
Does any of this ring any bells?
Give us more information and we might be able to help further...
Regards,
Darren.