Solution to login problems (Firefox, Safari, IE).

If you have a user account but have been unable to log in recently, you might be experiencing a known problem with the Firefox browser (the problem has also been reported with Safari and Internet Explorer).  The solution is to clear all your browser’s “cookies”.

In Firefox, go to Tools Clear Private Data.  A selection window will pop up.  Put a checkmark next to “Cookies” and uncheck everything else,  then click the “Clear Private Data Now” button.

(We learned of this solution from Ivan Marchenko, in this comment at  Thanks, Ivan!)