A method in the disclosure includes: receiving, from an information device, a device password which is used for controlling a target device via an in-house server apparatus and which is input on the information device using a setting screen; managing a device ID of the in-house server apparatus, a user ID, and the device password in association with one another; transmitting the device password to the in-house server apparatus to cause the in-house server apparatus to manage the device ID and the device password; transmitting, when login to an out-of-house server apparatus is authenticated, an authentication screen to the information device; receiving, from the information device, an input password that is input on the information device using the authentication screen; and when the received input password is identical to the device password that is associated with the user ID, approving a control of a target device by the information device.