While the game server may be online currently, it's still under construction. Meaning some maps like Lonely Cave are failing to connect to the front server and there has been some chat hiccups/glitches every now and then. Everyone is experiencing this so it isn't just you. My guess is if you have some older characters scattered throughout different maps, try to log in on them. However, if none of them work for you or if you have no older characters, just try to sit tight for the staff is working hard in getting this fixed.