I usually fat finger something or make a dumb mistake configuring myself when I can't connect to the Services interface. The correct setup is:
You HAVE TO STATICALLY assign this to your NIC, it does not provide DHCP.
YOUR IP: 192.11.13.5
YOUR SUB: 255.255.255.252
You don't need a gateway.
You need to use a crossover cable
Once this is done, if you are using a windows machine open a command prompt and do an IPconfig (ifconfig for you linux users) you should see that the NIC is UP or Connected. If it says "Disconnected" you have a physical layer issue, try another cable.
Once it's connected, try pinging the service interface's IP, 192.11.13.6 Does this work?
If it does work, then open a browser, in the address bar go to:
http://192.11.13.6
Try to telnet to 192.11.13.6 you should get a login prompt even if your login doesn't allow you bash access.
If after all this you still cannot access the web interface two things might be the problem:
1) The web service has crashed, is disabled or is otherwise not running
2) Someone has disabled web access.
You can try restarting the S8300, but you will probably need someone with bash access to check to see if the webaccess is enabled.
Hope this helps,