I'm using Windows 7. Just uninstalled Google Chrome and installed firefox, but now I can't login.

After Login it seems I logged in already:
![enter image description here][1]

but when it automatically directed to the math exchange page, I'm still not loggin yet....
![enter image description here][2]

what could I do?


  [1]: https://i.sstatic.net/DVAwG.png
  [2]: https://i.sstatic.net/1icL7.png