Watch can't sign in to iCloud I set up a new Apple Watch yesterday by restoring from the backup of a previous watch. The watch from which the backup came was successfully logged in to my iCloud account. But with this watch, each time I have attempted to log in, I am getting an error:



The error is "Could Not Sign In - There was a problem connecting to the server"

The iPhone I'm doing this on is connected to the internet and logged in to iCloud. I am able to authenticate to iCloud in other apps (verifying App Store purchases, for example). It seems to be just this one task that can't connect. 

This has persisted through restarts of both the phone and the watch. Is there a fix? How should I go about troubleshooting?

Apple Watch series 3, watchOS 4.2; iPhone 8, iOS 11.2.5.
Try updating to the latest iOS/watchOS version.  

A new update (11.2.6/4.2.3) just came out and it might fix whatever is causing your issue.