Drupal user login page error and issue redirected to user/login?destination=user

On Drupal 7, you suddenly experience a login user page being redirected to a non-working or blank page at /user/login?destination=user. On below example, you notice the login form will not work as no form fields are being displayed. Even on source code, the same form fields are missing.

Drupal user login error, redirected page

Reported workarounds and solutions:

  • Cache - clearing some core and module cache 
  • Globalredirect module - disabling the redirect module
  • Rewritebase on .htaccess - uncommenting out and setting the proper sub-directory if applicable

On above issue, the culprit seems to be a conflict with the Betterlogin module. Disabling the betterlogin module worked.