An unknown error occurred when Apple Watch failed to verify.

Does the subject want to ask "what is the unknown error of Apple Watch verification failure?" Network problems, application problems.

1, network problem: unstable or slow network connection will lead to authentication error. Make sure that both iPhone and AppleWatch are connected to a good WiFi network or mobile data (cellular data) network.

2. Application problem: Applications in AppleWatch will lead to verification errors. Close all applications and verify again.