The best next step is to schedule the firmware update during a maintenance window. This ensures that there is minimal impact on the network service and clients are least likely to be affected, as there would be fewer active users. Informing users about the downtime is also important for transparency and to prevent unexpected disruption of their work. Performing the update immediately without scheduling could result in unnecessary disruptions during business hours, while further unnecessary troubleshooting is a waste of resources if the solution is already identified. Escalating the case without attempting the known solution would not follow proper troubleshooting protocol.