There's more to experience when you log in!
I'm not able to see any module/service/page that comes through port 8080 outside the machine, where Spectrum runs, except for Server Demo Page. Port is opened to everyone in firewall and proxy and therefore, there shouldn't be any restriction problems. Is there any setting in Spectrum itself that could cause that kind of behavior or is this more likely an issue with proxy/firewall?
As everything through that port is temporary opened to everyone, you can try it yourself: https://kovruum.ee:8080Server is windows.