Problems with the log in

When I open the launcher, it costantly asks me to log in, even if I select the option of being always logged in. Also, when I want to play in multiplayer, It constantly tells me that I have to restart my launcher. And thats because It logged out and I end having an "Invalid Session". On the other hand, when I try to log in, I appears like I put the password wrong (even when its right) and I have to try many times with the same password to access.