My Apple Watch got iCloud lock

Hi

You are describing Activation Lock, which prevents unauthorised use of Apple Watch if it is lost or stolen.

If the watch is locked to your own account, but you are having issues with your credentials:

It may help to follow the instructions here:

If you still need assistance, contact Apple Support or make a Genius Bar reservation, taking along your Apple Watch and your original proof of purchase for it:

• Contact - Official Apple Support
• https://twitter.com/applesupport
• http://www.apple.com/retail/geniusbar/

If the Apple Watch is pre-owned and locked to the previous owner's account:

• You will need the previous owner (who may not be the seller) to either enter their Apple ID and password on your iPhone or to turn the feature off via https://www.icloud.com/ (by signing in with their Apple ID > Find My iPhone > All Devices, then select the Apple Watch > Erase Apple Watch > Next until erased > click X next to the watch).
• If you cannot arrange for the previous owner to do this, you should return the watch for a refund.
• You will not otherwise be able to use the watch. There is no way around this security feature.

More information:

About Activation Lock on your Apple Watch - Apple Support