In a server, a memory stores first correlation information for correlating first group identification information with both first device information assigned to a first communication device and second device information assigned to a second communication device. A first group includes the first communication device and the second communication device. In a case where device information matching the first device information and authentication information matching the first authentication information are received from the first communication device, the processor transmits to the first communication device a second file generated using a first file which is stored correlated with the first authentication information in the memory. In a case where device information matching the second device information and authentication information matching the first authentication information are received from the second communication device, the processor transmits to the second communication device the second file.