After upgrading the Active Administrator server, when you try to open the console, an error similar to following may occur:
"Unable to establish a connection with the server. The message with Action <action> cannot be processed at the receiver, due to a ContractFilter mismatch at the EndpointDispatcher. This may be because of either a contract mismatch (mismatched Actions between sender and receiver) or a binding/security mismatch between the sender and the receiver. Check that sender and receiver have the same contract and the same binding (including security requirements, e.g. Message, Transport, None)"