I am no longer able to login to zoho ...what changed over the weekend with Zoho?

I am no longer able to login to zoho ...what changed over the weekend with Zoho?

Hi,

Starting on Monday, after I click login, I go to a blank screen that says please wait and it just hangs there.  I use zoho daily and have not made any changes to my system (Mac 10.5.8, Firefox 12).  Can someone advise if zoho has made some changes affecting Firefox users? 

thanks