In DNN 4.5.2 if you have an account login module on your home page, then you may experience a "hang" or continuos redirect when logging in.
The problem is in the signin.ascx.vb file on line 495. If you comment out the following lines it will remove this problem.
' Else
' ' if user is already authenticated then redirect to current page
' Response.Redirect(NavigateURL(), True)
I have also attached an updated file which you use to overwrite the one in the admin/security/signin.ascx.vb
This is a quick fix, I'll see if I can determine what the original developer was really trying to do and may update this post later so be sure to subscribe to notifications on this thread.