Sometimes older versions of pages are cached in your browser and can provide challenges when trying to navigate and/or log in. A good practice is to clear your cached files. Below are some instructions on how to do so in Firefox.
To get started, click on the Menu button towards the top right of the browser as shown above.
Next click on "Options".
From this window, first click on "Advanced". Then click on the "Network" tab. After you have completed that, click on "Clear Now" as shown above. Finally click on "OK" to close the Options window.