Hello,
It's an isp routing issue. You can check it yourself trying any vpn service trial you like or contacting your ISP with routing change request

Lets check similar cases of RIOT games and Blizzard. Both are building/built their OWN infrastructure with immense capital investment, because they've encountered similar issues with ISPs not reacting or even caring about similar player problems.

Do you really expect Kakao, being a pulisher with a HQ in Korea, will fix your own connection problems? It is definetely negotiating with ISPs, but from my experience with medium sized game developers it will not solve a problem reliably or fast.

Thank You!!!


I didn't find the right solution from the Internet.
References
https://community.blackdesertonline.com/index.php?threads/its-not-server-issues.100768/
Motion Graphics Video