Refer to the exhibit. A WAN Edge device may recently added to vManage, but a control connection could not be established. Which action resolve this issue?

A Root CA certificate mismatch would prevent TLS/DTLS tunnel establishment due to trust issues, but the primary action for a newly added device failing to connect often involves serial number synchronization with vBond first.

ZTP issues and smart account credentials are typically relevant during initial automated provisioning, not usually the direct cause of a control connection failure after the device has already been added to vManage.

Installing bootstrap code is part of the initial device bring-up to join the fabric, and checking for CSR (Certificate Signing Request) is part of certificate enrollment, which often follows successful initial connectivity, not the direct solution for a serial number-related connection problem.

When a WAN Edge device is added to vManage, its serial number is registered for authentication. For the WAN Edge to successfully establish a control connection, vBond must also be aware of this serial number to validate the device. Sending the serial number to vBond from vManage ensures this critical synchronization, allowing the control connection to form.