The Dev Pages

 1) feature does X (BaseApp.UIWeb.Test.Acceptance.TheTest)
     apps/ui/test/ui_web/acceptance/the_testexs:13
     ** (RuntimeError) invalid session id
     code: |> session_login()
     stacktrace:
       (wallaby) lib/wallaby/httpclient.ex:136: Wallaby.HTTPClient.check_for_response_errors/1
       (wallaby) lib/wallaby/httpclient.ex:56: Wallaby.HTTPClient.make_request/5
       (wallaby) lib/wallaby/webdriver_client.ex:254: Wallaby.WebdriverClient.visit/2
       (wallaby) lib/wallaby/driver/log_checker.ex:6: Wallaby.Driver.LogChecker.check_logs!/2
       (wallaby) lib/wallaby/browser.ex:963: Wallaby.Browser.visit/2
       (ui) test/support/acceptance/rivendell_wallaby_session.ex:73: Rivendell.UIWeb.Test.Support.Acceptance.RivendellWallabySession.session_login/1

The solution for this was to run: brew cask upgrade chromedriver and possibly to update your chrome browser. The comments on this issue/repo were very helpful: https://github.com/elixir-wallaby/wallaby/issues/468