Gmod Server, I can't join but other's can.

So i started my own garrysmod server via hldsupdatetool and when i first got it, i could play on it. (also i’m running the server on the same computer that i play it on)…Then later on i started to get the gamemode DarkRP and other addons like Ulx
It’s also port forwarded and other players on my SAME internet connection are able to play on it but i can’t…It says when i try to join my own server, “connection failed after 4 retries” and also i can’t join any other server when i have my gmod server
running…anyone know how to fix it?