mix deps.get failed (seems missing ssl?) : <p>I'm sorry but I'm new to Elixir. while building phoenix application, <code>mix deps.get</code> failed with an error.</p>

<pre><code>% mix deps.get
Could not find Hex, which is needed to build dependency :phoenix
Shall I install Hex? [Yn] y
** (MatchError) no match of right hand side value: {:error, {:ssl, {'no such file or directory', 'ssl.app'}}}
    (mix) lib/mix/utils.ex:409: Mix.Utils.read_httpc/1
    (mix) lib/mix/utils.ex:354: Mix.Utils.read_path/2
    (mix) lib/mix/local.ex:107: Mix.Local.read_path!/2
    (mix) lib/mix/local.ex:86: Mix.Local.find_matching_versions_from_signed_csv!/2
    (mix) lib/mix/tasks/local.hex.ex:23: Mix.Tasks.Local.Hex.run/1
    (mix) lib/mix/dep/loader.ex:140: Mix.Dep.Loader.with_scm_and_app/4
    (mix) lib/mix/dep/loader.ex:98: Mix.Dep.Loader.to_dep/3
    (elixir) lib/enum.ex:1043: anonymous fn/3 in Enum.map/2
%
</code></pre>

<p>erlang and elixir has been installed via <a href="https://github.com/yrashk/kerl" rel="noreferrer">kerl</a> and <a href="https://github.com/HashNuke/asdf" rel="noreferrer">asdf</a>.
and my installation log is here <a href="http://otiai10.hatenablog.com/entry/2016/02/03/154953" rel="noreferrer">http://otiai10.hatenablog.com/entry/2016/02/03/154953</a></p>

<p>envirionment</p>

<ul>
<li>MacOS: 10.11.2</li>
<li>Erlang: 18.0</li>
<li>Elixir: 1.1.1</li>
</ul>

<p>What is happening and what should I do?</p>
