pwoni

well, you could try reinstalling and updating your drivers for your hardware. if that doesn't help - see if your router has issues. check the provider/check your routers connectability, mine for example lets me go to a website that shows me if i had any dcs or if my connection was unstable at some point. i don't know your hardware and the situation you live in. are the cables alright? is the cable you use broken? i don't think that this is the issue, i trust you know your stuff. try it with reinstalling first and check this https://www.howtogeek.com/174068/how-to-identify-which-hardware-component-is-failing-in-your-computer/ i hope you find out what's wrong, mate

did it work now? check if you can play any other mmo and if that doesn't work either it could be a hardware issue. at least you can figure out the issue and move on from there, you know?

i couldn't login the whole day too but i have no idea what your problem might be though tbh. https://account.ncsoft.com/settings/authorizedlocation/index go here and remove every ip, restart your computer and your router just to check that off the list too. after that - if it still doesn't help - repair the files of the game, check your antivirus if it blocks the game.