Never forget anymore if you do / want to do with servers, if join on LOCALHOST its ALWAYS ALWAYS working also as 127.0.0.1 this is your loopback adress!
And check really good again, if you see him on the web server list from FiveM its also in the list if you start your game after you started the server!
previous server list cashed the list, if you where to early needed to restart to see it on the list! Aswell direct ip will work localhost or when proper config from external.
I expect an answer with the issue!