elixir error

web_1 | ** (EXIT from #PID<0.49.0>) an exception was raised:
web_1 |     ** (FunctionClauseError) no function clause matching in Regex.match?/2
web_1 |         (elixir) lib/regex.ex:157: Regex.match?(~r/^\/([^\/])+$/, nil)
web_1 |         (ecto) lib/ecto/repo/supervisor.ex:85: Ecto.Repo.Supervisor.parse_url/1
web_1 |         (ecto) lib/ecto/repo/supervisor.ex:21: Ecto.Repo.Supervisor.config/3
web_1 |         (ecto) lib/ecto/repo/supervisor.ex:107: Ecto.Repo.Supervisor.init/1
web_1 |         (stdlib) supervisor.erl:272: :supervisor.init/1
web_1 |         (stdlib) gen_server.erl:328: :gen_server.init_it/6
web_1 |         (stdlib) proc_lib.erl:239: :proc_lib.init_p_do_apply/3
web_1 | 10:22:24.968 [info] Running Mobil.Endpoint with Cowboy on http://example.com:4000
web_1 | {"Kernel pid terminated",application_controller,"{application_start_failure,mobil,{{shutdown,{failed_to_start_child,'Elixir.Mobil.Repo',{function_clause,[{'Elixir.Regex','match?',[#{'__struct__' => 'Elixir.Regex',opts => <<>>,re_pattern => {re_pattern,1,0,0,<<69,82,67,80,85,0,0,0,16,0,0,0,1,0,0,0,255,255,255,255,255,255,255,255,0,0,0,0,0,0,1,0,0,0,64,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,125,0,17,25,29,47,127,0,7,0,1,31,47,115,0,7,27,114,0,17,0>>},source => <<\"^/([^/])+$\">>},nil],[{file,\"lib/regex.ex\"},{line,157}]},{'Elixir.Ecto.Repo.Supervisor',parse_url,1,[{file,\"lib/ecto/repo/supervisor.ex\"},{line,85}]},{'Elixir.Ecto.Repo.Supervisor',config,3,[{file,\"lib/ecto/repo/supervisor.ex\"},{line,21}]},{'Elixir.Ecto.Repo.Supervisor',init,1,[{file,\"lib/ecto/repo/supervisor.ex\"},{line,107}]},{supervisor,init,1,[{file,\"supervisor.erl\"},{line,272}]},{gen_server,init_it,6,[{file,\"gen_server.erl\"},{line,328}]},{proc_lib,init_p_do_apply,3,[{file,\"proc_lib.erl\"},{line,239}]}]}}},{'Elixir.Mobil',start,[normal,[]]}}}"}
web_1 |