A processor of a server is configured to receiving a first registration request from a terminal, storing first account and first authentication data in a memory of the server in association with each other, transmitting the first authentication data to terminal, receiving a third registration request from a communication device, storing device identification data and second authentication data in the memory in association with each other, transmitting the second authentication data to the communication device, receiving a fourth registration request including the first authentication data and the second authentication data, and storing the first account data associated with the first authentication data included in the fourth registration request and the device identification data associated with the second authentication data included in the fourth registration request in the memory in association with each other.