Apple has updated its system status page to reflect ongoing issues with eleven iCloud-related services: Back to My Mac, Documents in the Cloud, iCloud Account & Sign In, iCloud Backup, iCloud Drive, iCloud Keychain, iCloud Mail, iMovie Theater, iWork for iCloud Beta, Photos and Find My iPhone, iPad, iPod touch and Mac. The services have been affected since around 12 AM Pacific.
iCloud is having issues since 3:11 AM EDT. http://t.co/z2kUNXWrcN RT if it s down for you as well #iclouddown - DownDetector (@downdetector) May 21, 2015
Update 7:05 AM Pacific: Apple's services are now restored per its system status page.
Article Link: iCloud, Mail, Photos and Other Apple Services Experiencing Issues [Updated]