Mac OS X error message "iCloud has stopped responding"
Since this morning I've been getting the error message "icloud has stopped responding" on my iMac. (OS X 10.10.5) I'm still able to access Calendar from iOS devices but updates are no longer appearing on Calendar on my iMac. All other internet connections are strong and working well. Any thoughts?
iMac, OS X Mountain Lion (10.8.5)