Do you have cookies enabled? There is a box in the sign in that says, "Remember me." Do you have it checked? If you do not have the box checked, or if you have cookies disabled, it will return you to the login screen as you describe. Also, have you been able to enter the vault ever before? I have pretty much the same problem. Used the Vault once before and now it doesn't work anymore. Infinite login demands, even though I'm already logged in. My "Remember me" box is checked and I have cookies enabled. Still doesn't work. Have tried deleting cookies so it gets new ones and still nothing.