Bypass fails test with TLS error

Background

I am using bypass to test an endpoint from my code. To achieve that I am using the following test code:

  @test_port 8082

  setup do
    bypass = Bypass.open(port: @test_port)

    %{
      bypass: bypass
    }
  end

  describe "get_user_orders/2" do
    test "returns {:ok, [placed_order]} ", %{ bypass: bypass } do
      
      # Arrange
      Bypass.expect(bypass, "GET", "/v1/profile/:username/orders", fn conn ->
        response = %{
          "payload" => %{
            "buy_orders" => [],
            "sell_orders" => [
              %{
                "item" => %{
                  "cs" => %{"item_name" => "Arcane Agility"},
                  "url_name" => "arcane_agility"
                }
              },
              %{
                "item" => %{
                  "cs" => %{"item_name" => "Abating Link"},
                  "url_name" => "abating_link"
                },
              }
            ]
          }
        }

        Plug.Conn.resp(conn, 200, Jason.encode!(response))
      end)

      # Act
      assert {:ok, [ ... ]} == Server.get_user_orders( "MY_SUPER_USERNAME")
    end
  end

Problem

The issue here is that even though the code seems to be working correctly, I get this very weird error (and the test fails) using bypass.

URL IS: "https://localhost:8082/v1/profile/MY_SUPER_USERNAME/orders"

12:08:18.188 [notice] TLS :client: In state :hello at tls_record.erl:561 generated CLIENT ALERT: Fatal - Unexpected Message
 - {:unsupported_record_type, 72}

  1) test get_user_orders/2 (AuctionHouseTest)
     apps/auction_house/test/integration/auction_house_test.exs:360
     Assertion with == failed
     code:  {:ok, [ ... ]} == Server.get_user_orders( "MY_SUPER_USERNAME")
     left:  {
              :error,
              {:tls_alert, {:unexpected_message, ~c"TLS client: In state hello at tls_record.erl:561 generated CLIENT ALERT: Fatal - Unexpected Message\n {unsupported_record_type,72}"}},
              "MY_SUPER_USERNAME"
            }
     right: {:ok,[...]}
     stacktrace:
       test/integration/auction_house_test.exs:467: (test)


Finished in 0.3 seconds (0.00s async, 0.3s sync)
7 tests, 1 failure, 6 excluded

The code is returning the correct result, but I get this weird TLS error. How can I fix this?