Does it work in other browsers? You can try to reset (power off/on) the router. You can remove all stored data from a specific domain via "Forget About This Site" in the right-click context menu of an history entry (Show All History or History sidebar). Using "Forget About This Site" will remove everything like bookmarks, cookies, passwords, cache, history, and exceptions from that domain, so be cautious and if you have a password or other data from that domain that you do not want to lose then make a note of those passwords and bookmarks. You can't recover from that "forget" unless you have a backup of the affected files. It doesn't have any lasting effect, so if you revisit such a 'forgotten' website then data from that website will be saved once again.