I just tried to learn some Elixir, in the latest ubuntu version. and Mix.install([ {:req, "~> 0.3"} ]) could not compile dependency :mint, "mix compile" fai

I just tried to learn some Elixir, in the latest ubuntu version. and Mix.install([ {:req, "~> 0.3"} ]) could not compile dependency :mint, "mix compile" failed. Also mix deps.get say that all dependencies are to date but then mix run gives again that could not compile dependency :mint, "mix compile" failed. So no good way to learn elixir.