A network device transmits, to a server, information of an event that has occurred in the network device, compares, with each of a first threshold and a second threshold greater than the first threshold, a metric that corresponds to a state of the network device pertaining to the event, and switches a method of communicating with the server based on the comparison. When the metric exceeds the first threshold while communicating with the server in a polling method with first communication intervals and is smaller than the second threshold, the method of communicating with the server switches to a polling method with second communication intervals that are shorter than the first communication intervals, and when the metric exceeds the second threshold while communicating with the server in the polling method with the second communication intervals, the method of communicating switches with the server to a push method.