正解:B
The issue indicated by POSTMAN in the exhibit is related to an expired token. When interacting with Cisco DNA Center API, a token is required for authentication purposes. This token has a limited lifespan for security reasons and must be renewed periodically. If a request is made with an expired token, the API will not authenticate the request, and an error will be returned, indicating that the token is no longer valid.
References: The Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials provide detailed information on how to interact with Cisco APIs, including handling tokens and managing their lifecycle.