that's the reason why we created a fat jar and uploaded it somewhere. However not using an "official" link was really disapproved by our ops. After some digging the problem comes from nailgun so

[resolve.coursier]
execution_strategy=subprocess

let us use

<https://oss.sonatype.org/content/repositories/releases/io/get-coursier/coursier-cli_2.12/1.1.0-M8/coursier-cli_2.12-1.1.0-M8-standalone.jar>