Keeping on booted out repetitively after approx. 2~3 mins

[Dragon Cross]

I've been logging in and out of Portal ever since its return.

After logging in and being redirected in the page, the page automatically boots me out back to the login screen.

Also, after approx. 5 seconds ~ 2 minutes of staying in the page, a message (due to Java being turned on automatically after logging in), it says "You don't seem to be logged in anymore" and gets booted back to the login page.

This has happened to me since May up until now. I've used Chrome and Firefox to log in, and has the option to keep my log in ID and password saved on my computer.

This wasn't like this in the past, I don't know if I am the only one who is experiencing this.