I had the issue that the links were returning aboutblank#blocked after I had moved containers onto a VPN network and removed all port references. It looks like it might be because the system is unable to populate one of the dynamic fields in the webui template, either IP or PORT and so just spits out a URL that doesn't work. Look to see you have the ports allocated to the containers and there may be something about it being unable to find the IP address of the system?
As other people have mentioned, the workaround seems to be to hardcode the web UI links, e.g http://192.168.1.100:8080, this setting can be accessed from teh conainter edit page under the "advanced" settings (activated by the advanced button in the top right of the page).
As an extra note, I had issues simply adding 192.168.1.100 or just a port number in the web UI field, it would always add a / between the IP address and whatever was put after. It seems to resolve this you either need to use the default [IP]:[PORT] template or use a full http:// url
