It is unclear what may be causing this to occur for you, but it is possible that your browser has cached the site pages and the cached pages could be causing a difficulty. I suggest that you clear the cache of your browser, close it and then reopen it prior to trying again. For Firefox, you can clear the cache:
Please click on the 'Firefox' menu button at the top left of the browser and then mouse over the 'History' menu on the right side of the resulting pop up menu. Click on "Clear recent History..." and ensure the boxes next to "cache" and "cookies" are checked, and then click the "Clear Now" button. Also, please ensure that only one browser window is open when you are doing this or your cache may not empty properly.
If the difficulty persists after this, please file a support case from the Help tab of your account so we can look into this further.