Yep, I've checked everything. The fact is that I can connect with my account on webstie but not ingame, using exactly the same account, so I can't understand what could be the problem here :/. I have even made a Full check files with updater to get every file to play the server, but I still can't log into. I created 3 accounts because no one was working, and I am completely sure that my ID/Passwords are the corrects, checking CAPS, and everything I can check.
By the way, I am playing with english client, but I don't think it matters at all, because I created my account here https://www.rpg-club.org/
at Register tab.
Thank you for answering.