Some network element(switch/router) is reachable through ping, but in topology, the state of the network work is offline and can not be refreshed and deleted.
Step 1: Change the firewall setting to cancel the access limit to the network element;
Step 2: Apply and load the formal License again.
• The network element is not allowed to be visited in the firewall setting.
• In the net management, first, use the temporary License to add such network element, then replace the temporary License with formal License, while the manage License of such network element is not contained in formal License.
As the control mechanism of temporary License and formal License is different, please add the network element under the formal License.