It seems Lost Ark blocks Mudfish nodes
Following tips are inspired by users' experiences but it isn't 100% guaranteed way.
I'm not sure it worked for you but you can try to Full VPN mode then make a Korean account then get the stove client manually at http://www.onstove.com/
Closing all web browsers before passing Xigncode would be better for launch the game. If you REALLY have will to play the game, you can consider to use Xiaomi Mi WiFi Nano / Youth (R1CL) or Mudfish for ipTIME router.
You can put Mudfish program into them, not into PC. But actually we're not sure is the Mudfish preinstalled ipTIME shipping properly to overseas. If you get that Xiaomi Nano R1CL anyhow, you can install it yourself
Bypassing Lost Ark with a Mudfish router is an experimental way and we can't guarantee this is always working successfully