Getting: (exit) shutdown: failed to start child: DBConnection.ConnectionPool ** (EXIT) exited in: GenServer.call(DBConnection.Watcher

Why I’m getting this error when trying to dynamically connect to repo?
insert.ex file

{:ok, _} = Application.ensure_all_started(:req)
    ct = %{
      chain: "ethereum",
      coin: "ETH",
      transaction_value: 12.345,
      transaction_charged: 1.234,
      ref: "test_ref",
      payload: "test_payload",
      public: "test_public",
      private: "test_private",
      status: false
    }
    
    default_dynamic_repo = MyApp.Repo.get_dynamic_repo()

    {:ok, repo} =
      MyApp.Repo.start_link(
        name: :gatinhos,
        hostname: "localhost",
        username: "pedri",
        password: "1234",
        pool_size: 1
      )
    
    try do
      MyApp.Repo.put_dynamic_repo(repo)
      MyApp.Repo.all(Post)
    after
      MyApp.Repo.put_dynamic_repo(default_dynamic_repo)
      Supervisor.stop(repo)
    end
  
  

application.ex

defmodule TestesPay.Application do

  use Application

  def start(_type, _args) do
    Dotenv.load()
    children = [
      MyApp.Repo,
    ]

    opts = [strategy: :one_for_one, name: Myapp.Supervisor]  # Add a space after name:
    Supervisor.start_link(children, opts)
  end
end

mix.exs file`defmodule TestesPay.MixProject do

  use Mix.Project

  def project do
    [
      app: :testes_pay,
      version: "0.1.0",
      elixir: "~> 1.16",
      start_permanent: Mix.env() == :prod,
      deps: deps()
    ]
  end

  # Run "mix help compile.app" to learn about applications.
  def application do
    [
      extra_applications: [:logger, :postgrex],
      mod: {TestesPay.Application, []}
    ]
  end

  # Run "mix help deps" to learn about dependencies.
  defp deps do
    [
      {:req, "~> 0.5.0"},
      {:ecto_sql, "~> 3.6"},
      {:postgrex, "~> 0.19.1"},
      {:rustler, "~> 0.34.0"},
      {:dotenv, "~> 3.0"},
      {:decimal, "~> 2.0"}
      # {:dep_from_hexpm, "~> 0.3.0"},
      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
    ]
  end
end
** (exit) shutdown: failed to start child: DBConnection.ConnectionPool ** (EXIT) exited in: GenServer.call(DBConnection.Watcher, {:watch, DBConnection.ConnectionPool.Supervisor, {DBConnection.ConnectionPool.Pool, {#PID<0.215.0>, #Reference<0.226797208

I dont need to load it dynamic, but I couldnt also connect via the default connection in the Ecto docs via config.,exs
i’m able to give cli commands suach as Ecto migrate etc and it connects to db make changes, but querying it by code isnt working