Can't login to Icloud on my Imac
So I have an Apple account and I can login to Icloud on the web, on my Ipod and on my Macbook Pro, but not on my Imac. When I go to preferences and the Icloud panel, login attempts just get me the error messages, as below. Why can't I login on my Imac?
iMac, Mac OS X (10.7.3)