API: Error with scope to get Authorization Code from My app to Alexa App (browser)

Working fine with the Below URL (scope: Profile) get the Auth code from Amazon.

https://www.amazon.com/ap/oa?client_id=[ClientID]&scope=profile&response_type=code&redirect_uri=<redirectURL>&state=<state>

Not working while using the scope alexa::skills:account_linking with below URL

https://www.amazon.com/ap/oa?client_id=[ClientID]&scope=alexa::skills:account_linking&response_type=code&redirect_uri=<redirectURL>&state=<state>

Error Message:
{“error_description”:”An unknown scope was requested”,”state”:””,”error”:”invalid_scope”}

In skills, added this (alexa::skills:account_linking) scope on account linking.

Please suggest.