Redirect loop with "drupal_goto" function

I got the problem of redirect loop when enable the module and set it to On restricted pages. Tested with Chrome and IE. Start from fresh login, redirect loop will appear. But if I already logged-in, I won't see this problem.

Then, I found that if I comment out drupal_goto in function _securesite_user_login function, it will works fine. But the page after login will show 2 pages below :

Page not found - The requested page "/" could not be found.
Access denied - You are not authorized to access this page.

Just reload the page again and it will work fine.

Update :

After test again after fresh login, I got error below :

Service Unavailable

The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

Additionally, a 503 Service Unavailable error was encountered while trying to use an ErrorDocument to handle the request.

Do the refresh after error and everything works as it should.