Automatically accept all SDK licences

Question

Since gradle android plugins 2.2-alpha4:

Gradle will attempt to download missing SDK packages that a project depends on

Which

Answer 1

Copy the entire licenses/ directory and paste it into the Android SDK home directory on the machine where you wish to build your projects.

https://developer.android.com/studio/intro/update.html#download-with-gradle

this resolved the issue for me