This Apple ID cannot be used to unlock this apple watch?

I note you specifically mention an Apple ID issue with your Watch, which is different from a forgotten passcode.

This support article has information about Activation Lock on your Apple Watch and how to turn it off. --> About Activation Lock on your Apple Watch - Apple Support

If this is because you have forgotten the required information, this document tells you the various ways you can try to discover your forgotten Apple ID --> If you forgot your Apple ID email address or phone number - Apple Support Note that typically this is an email address you use. This document outlines what to do If you forgot your Apple ID password --> If you forgot your Apple ID password - Apple Support

or go directly to this link --> http://iforgot.apple.com/

If you still need help:

Contact Apple for help with Apple ID account security "This article provides country-specific Apple Support contact information for customers seeking help with their Apple ID password or other security-related issues." Click here --> Contact Apple for help with Apple ID account security - Apple Support

If you are unsuccessful in discovering the account information required to unlock the Watch, Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Do this online at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not state what currently constitutes proof. Prior to this new online service Apple typically required the original receipt issued by an Apple Authorized dealer and documented provenance (so typically it would be the original owner who does this, or a descendant with legal proof of ownership). Apple recommends you keep your receipt after you buy an Apple device. --> Keep your receipt after you buy an Apple device - Apple Support

If you're using an Apple ID other than the one it's locked to, because the activation lock is an anti-theft measure.

If you're using the Apple ID that it's locked to, because there's a problem on Apple's servers. Click here and submit an unlock request.

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You need your Apple Watch passcode to unlock your Apple Watch, see -> If you forgot your Apple Watch passcode

If you forgot your Apple Watch passcode - Apple Support

See the following Apple articles:

Set up your Apple Watch -> Set up your Apple Watch – Apple Support (UK) 

The Apple Watch app -> The Apple Watch app – Apple Support (UK)

Apple Watch user guide -> https://books.apple.com/book/id6442854652