A communication terminal, comprising: a processor configured to control the communication terminal to perform a first function and a second function, the first function being performed without requiring communication with other communication terminal, and the second function being performed through communication with the other communication terminal, the processor being configured to: control to transmit first authentication information to a first server to request for the first function, the first server being configured to perform a first authentication process of determining whether the communication terminal is allowed to perform the first function based on the first authentication information, characterized in that in response to a result of the first authentication process indicating that the communication terminal is allowed to perform the first function, the processor is configured to control to transmit second authentication information to a second server to request for the second function, the second server being configured to perform a second authentication process of determining whether the communication terminal is allowed to perform the second function based on the second authentication information, wherein the processor is further configured to receive the second authentication information from a third server that transmits the second authentication information based on the result of the first authentication process indicating that the communication terminal is allowed, the result of the first authentication process including user identification information that is included in a request for the second authentication information transmitted by the communication terminal to the third server. a processor configured to control the communication terminal to perform a first function and a second function, the first function being performed without requiring communication with other communication terminal, and the second function being performed through communication with the other communication terminal, the processor being configured to: control to transmit first authentication information to a first server to request for the first function, the first server being configured to perform a first authentication process of determining whether the communication terminal is allowed to perform the first function based on the first authentication information, characterized in that in response to a result of the first authentication process indicating that the communication terminal is allowed to perform the first function, the processor is configured to control to transmit second authentication information to a second server to request for the second function, the second server being configured to perform a second authentication process of determining whether the communication terminal is allowed to perform the second function based on the second authentication information, wherein the processor is further configured to receive the second authentication information from a third server that transmits the second authentication information based on the result of the first authentication process indicating that the communication terminal is allowed, the result of the first authentication process including user identification information that is included in a request for the second authentication information transmitted by the communication terminal to the third server. control to transmit first authentication information to a first server to request for the first function, the first server being configured to perform a first authentication process of determining whether the communication terminal is allowed to perform the first function based on the first authentication information, characterized in that in response to a result of the first authentication process indicating that the communication terminal is allowed to perform the first function, the processor is configured to control to transmit second authentication information to a second server to request for the second function, the second server being configured to perform a second authentication process of determining whether the communication terminal is allowed to perform the second function based on the second authentication information, wherein the processor is further configured to receive the second authentication information from a third server that transmits the second authentication information based on the result of the first authentication process indicating that the communication terminal is allowed, the result of the first authentication process including user identification information that is included in a request for the second authentication information transmitted by the communication terminal to the third server.