Correct Log-out

Hi there.
I'm writing a method for a log-out in the application. I simply delete credentials and pop the actual View from the stack for return to the previous page that is the LoginView.
Now, when I log-in again (without stop the application, it still runs), I obtain a Java.Lang.IllegalStateException. Probably it is because I have to re-initialize every object? Or what?

Thanks ^^