I just setup my server, but when I try join, it says it is down. I have forwarded the ports, and I know I have done everything properly, because I have setup another server which works. I can connect fine with the local server url, but when other people try connect, they get the thing saying it's probably down.
Sounds to me like the ports are down, if you can connect locally it means that the server is definitely running. You're either providing the wrong externalurl or the ports are blocked. Have you made sure the ports are open and active?
It says it can't see me, but it has worked before :S My modem must have changed something...
Jack had a similar problem, he forwarded his ports and everything was dandy, then the next time he booted up his PC and ran the server something wasn't working. It turned out that he had to assign specific ports to specific internal IP addresses, and his internal IP had changed, so it was forwarding to the incorrect computer on the network.
is it possible that this is the same problem that you're experiencing? It seems to me that it's likely that you've forwarded to one location and now that location has changed.