Trying to get Up and Running - (Mix) The task "phx.new" could not be found

I am trying to build a simple hello-world web app with Phoenix, and following the instructions for Up and Running, but I didn’t get very far.

My OS is Amazon Linux 2 (based on Red Hat Enterprise Linux (RHEL) 7)
I was able to get Erlang and Elixir successfully installed with asdf:
elixir 1.15.4-otp-26
erlang 26.0.2

The output when I run mix archive.install hex phx_new:

Resolving Hex dependencies...
Resolution completed in 0.012s
New:
  phx_new 1.7.7
* Getting phx_new (Hex package)
All dependencies are up to date
Compiling 11 files (.ex)
** (ErlangError) Erlang error: {:notsup, {~c"hash.c", 112}, ~c"Digest type not supported in this cryptolib"}
    (crypto 5.2) crypto.erl:2200: :crypto.hash(:blake2b, "defmodule Mix.Tasks.Local.Phx do\n  use Mix.Task\n\n  @shortdoc \"Updates the Phoenix project generator locally\"\n\n  @moduledoc \"\"\"\n  Updates the Phoenix project generator locally.\n\n      $ mix local.phx\n\n  Accepts the same command line options as `archive.install hex phx_new`.\n  \"\"\"\n\n  @impl true\n  def run(args) do\n    Mix.Task.run(\"archive.install\", [\"hex\", \"phx_new\" | args])\n  end\nend\n")
    (mix 1.15.4) lib/mix/compilers/elixir.ex:1104: Mix.Compilers.Elixir.each_file/5
    (mix 1.15.4) lib/mix/compilers/elixir.ex:1009: Mix.Compilers.Elixir.compiler_loop/4
    (mix 1.15.4) lib/mix/compilers/elixir.ex:173: Mix.Compilers.Elixir.compile/7
    (mix 1.15.4) lib/mix/state.ex:15: Mix.State.lock/2
    (mix 1.15.4) lib/mix/task.ex:447: anonymous fn/3 in Mix.Task.run_task/5
    (mix 1.15.4) lib/mix/tasks/compile.all.ex:124: Mix.Tasks.Compile.All.run_compiler/2
    (mix 1.15.4) lib/mix/tasks/compile.all.ex:104: Mix.Tasks.Compile.All.compile/4

The output when I run mix phx.new hello:

** (Mix) The task "phx.new" could not be found
Note no mix.exs was found in the current directory

I did see the similar post in elixir forum and the ticket in github, but I don’t know how to apply the work-around someone suggested:
“in Mix.Tasks.DepsTest - patching those lines to use :sha256 works.”

If that is the best way to “fix” this, could someone please explain it more in-depth for me, please? I’m a complete newbie. Or if there is a different/better way, feel free to explain that instead.

Any help would be greatly appreciated, thanks!

Your best bet for now is probably to just use Elixir 1.14 instead of 1.15.

Yep, using elixir 1.14.5-otp-26 did the trick! Thank you!