Downloaded PandaWoW client all over again. Followed carefully through the required steps, still didn't worked. I tried changing the password to another one, still didn't worked. After that I insisted a bit longer and somehow I managed to connect (with the same account and password I failed to like 5 times before). I'm not sure if it's fixed for good, I have no ideea what really fixed it. I just hope it won't happen again...