An information processing system including one or more computers, comprising: a reception part configured to receive a request from a transmitter, the request being a request addressed to a first destination and including user information of the transmitter in a first information item of the request, or a request addressed to a second destination and including the user information of the transmitter in the first information item of the request and user information of a user designated by the transmitter in a second information item of the request; a determination part configured to determine, in response to receiving the request, whether the transmitter is an authorized user of one or more authorized users having operation authority or not, based on the user information of the transmitter in the first information item of the request, when the received request is the request addressed to the first destination, and whether the designated user is an authorized user of the one or more authorized users or not, based on the user information of the designated user in the second information item of the request, when the received request is the request addressed to the second destination; a generation part configured to generate authority identification information being a PIN code for identifying operation authority to operate an apparatus to be provided based on a result of the determination; and a transmission part configured to transmit the authority identification information to the transmitter of the request, in response to determining that user information of the authorized user is included in the received request, wherein the information processing system transmits the authority identification information to the transmitter, in response to the determination that the transmitter is the authorized user and determining an absence of a data attachment to the request, when the received request is the request addressed to the first destination, wherein the generation part is configured to generate the authority identification information with respect to the request addressed to the first destination, in response to the determination that the transmitter is the authorized user, and generate the authority identification information with respect to the request addressed to the second destination, in response to the determination that the designated user is the authorized user. a reception part configured to receive a request from a transmitter, the request being a request addressed to a first destination and including user information of the transmitter in a first information item of the request, or a request addressed to a second destination and including the user information of the transmitter in the first information item of the request and user information of a user designated by the transmitter in a second information item of the request; a determination part configured to determine, in response to receiving the request, whether the transmitter is an authorized user of one or more authorized users having operation authority or not, based on the user information of the transmitter in the first information item of the request, when the received request is the request addressed to the first destination, and whether the designated user is an authorized user of the one or more authorized users or not, based on the user information of the designated user in the second information item of the request, when the received request is the request addressed to the second destination; a generation part configured to generate authority identification information being a PIN code for identifying operation authority to operate an apparatus to be provided based on a result of the determination; and a transmission part configured to transmit the authority identification information to the transmitter of the request, in response to determining that user information of the authorized user is included in the received request,