Cannot Join My Dedicated Server

Pretty much I have a problem where if I define my IP as 192.168.2.100 which is my computers local IP (my routers IP being 192.168.2.1 and internet IP being 220.245.100.87) other people will be able to join using my internet IP but I cannot join my own server on the same computer i’m hosting it on. I’ve talked to 3 people who host dedicated servers on gmod and they can all join their own servers on the same PC they host from(except one who uses server boxes)

I use srcds, I have port forwarded correctly and done almost everything right seeing that other people can join my server. I also know that joining your own server makes it lag quite a lot and decreases its performance. My server is a private server for only me and a few friends to mess around on. It’s essentially a build server with many addons where I can show my friends cool contraptions and muck around with the addons, so really I don’t care too much about performance so long as it works.

So I just really want to know what I have to do for the server to allow me to play on it.
Oh and by I can’t join I mean I can find it in LAN but when I join it just fails connecting after 4 retries.

Any help is appreciated.