Trouble logging in (disconnection)

I'm new to Path Of Exile; I play POE on Steam. When I first try to log into POE I get disconnected at least two to three times before I can log into the game. It says "Disconnected: Your Authentication for instance transfer was invalid.

In the lower left of the screen, it says, "an unexpected disconnection occurred". Sometimes I get disconnected when I use a town portal to return to town which is very frustrating because I lose my open portal.