There could be a few various problems;
One:
When you renamed the Cache, did you also change it in the client files as well? The client needs to know which Cache it is supposed to be loading in order for it to work successfully.
Two:
You have portforwarded your router? Do you have a no-ip account set up to hold a static IP? Otherwise, the IP on your computer changes every once in a while automatically, and if not set to static, you'll need to change the IP in the client files once more.
Three:
I am not calling you stupid, but this is quite a common problem that people don't tend to notice, but is your server actually open and running?
Four:
Make sure your firewall, or another program is not using/blocking the port. Otherwise the server will not run at all.
Hope I helped.