Gameguard problem?

[SOLO]

i'm having an issue today with running 3x l2 windows as usual. When i log in with 2nd window, first one lags or gets disconnected, 2nd one displays 'this will close your client' on character select.

I thought it was a login server lag, but this is completely different.

I've retried many times, got launched 2x somehow, but on 3x my same problem occurs, and even better - my WiFi traffic gets frozen at 0, and go back up as soon as i close at least one window. (yes, i am watching movies aside, so I noticed the freeze). No memory leaks/CPU overloads or game crashes. No recent updates on WIN10, was running fine whole event