Have you tried using a different browser on your PC, or a different PC, or temporarily disabling any antivirus or firewalls that could be causing the issue.
I understand you are frustrated, but you need to realise this isn't a typical fault with the NAS and is likely to be specific to your setup- including your computer and network. No one here yet knows much about either.
Perhaps you could tell us a bit about your network setup, what is connected to where, what firewalls, antivirus software, Windows version you have, what firmware version is running on the NAS. It's time consuming and boring to find out and answer these questions, but without some background information, it's impossible for any of us to try and figure out why something is not working for you.