I want to return Knight Online

Hello,

I have been a very old player since 2004. I wanted to return to Knight Online on quarantine days. I downloaded the game. I tried logging into the game in with my account and received a warning message said that "No such registered ID" on the login page.
What does this mean ?
After Then I tried to change my account password.
Now if i don't have an account. "No such registered ID."
When I want to change my account password. How do I got mail on my e-mail address? Anyway, I clicked on the link (change password) in the mail received. Unfortunately, It didn't work either.

I created a new account to explain my problem

HELP me
Best regrads