To the best of my knowledge, the PWO Server does not actively block anyone from establishing a connection to the game. If the server isn't actually down, you may want to check to ensure that software on your own computer - such as Firewall, Anti-Malware or Internet Security products - are not interfering with PWO's ability to connect to the internet.
I had this issue recently and I can give you the solution. If you go into your windows control panel language and region settings and set your keyboard language to english, and then set your computers region to english and then restart your computer and redownload the client it should work. It might also be a good idea if you have an IME installed with the language modes set to alpha numeric. If this doesn't work then i'm not sure what else you can try but it worked for me. It's because the characters used in some of the clients code get changed when you download it from a non roman alpha numeric region which interferes with the client preventing it from working.