PhoenixアプリでSendgridの"The from address does not match a verified Sender Identity. ..." エラーの解消

デフォルトで

lib/supac/accounts/user_notifier.ex

# ...

  # Delivers the email using the application mailer.
  defp deliver(recipient, subject, body) do
    email =
      new()
      |> to(recipient)
      |> from({"MyApp", "[e-mail]"}) # <- cause of error
      |> subject(subject)
      |> text_body(body)

    with {:ok, _metadata} <- Mailer.deliver(email) do
      {:ok, email}
    end
  end

# ...

となっているので

lib/supac/accounts/user_notifier.ex

# ...

  # Delivers the email using the application mailer.
  defp deliver(recipient, subject, body) do
    email =
      new()
      |> to(recipient)
      |> from({"MyApp", "[e-mail]"}) # <- fixed
      |> subject(subject)
      |> text_body(body)

    with {:ok, _metadata} <- Mailer.deliver(email) do
      {:ok, email}
    end
  end

# ...

などと有効なメールアドレスに変更することで解消できます。