Fatal Error/Unable to Load Config/Slowness in General

I have to be patient when logging in. Usually I have to wait for 3-5 mins each step of logging in or I'd crash the client (shows either Fatal Error or Unable to load config depend on the steps).
The problem continues in game as CM fails to load/load very slowly, Black Spirit Game loads slowly, and the Premium menu also the same. Combat, interaction with NPCs, storage are behaving normally. Just CM, Black Spirit Game, and Premium menu are extremely slow to load and prone to fail.
I have tried restarting modem, flushing dns, delete cached, delete files in AppData Roaming/Local, redownloading the game and nothing seems to permanently fix it.
Please help.