Apple’s system status page is noting that a small amount of users are experiencing an iCloud Mail outage. Apple reports the outage, which has lasted for over 17 hours, affects approximately 0.1% of all users.
9to5Mac reports that users affected by the outage are seeing a ‘Cannot Get Mail: iCloud is currently unavailable’ message. Apple hasn’t announced as to when affected users can expect their email service to be restored.
All other iCloud services appear to be operational.