A server is configured to establish a communication session between electronic devices, receive first information about a time range and second information about a location range from a first electronic device, send third information to the first device, the third information being information about one or more users with whom a user of the first device establishes a human relationship, identify a user selected among the one or more users, store the first information and the second information in a database in connection with identifiers of the user and the identified user, monitor a location of at least one of the first device and a second device of the identified user based on the first and second information, and send, when one of the first or second device deviates from the location range, a notification message to the other one of the first or second device.