Maybe it's just temporary (I haven't seen that myself). Could you try these things to see if any of them help: * reload the stopped page using either Ctrl+r or Ctrl+Shift+r * closing the tab with the stopped page and re-opening the page in a new tab * exiting Firefox and starting it up again, then using History > Restore Previous Session to get your tabs back (note: assumes you are not using a private window and not clearing history when you close Firefox)