Why using socket SocketReceive can only send max5 number

[xiaoma]

In my pc, I creat a c++ client socket,and in RobotStudio, I creat a module about server socket, but when i send a string from client to server, the SocketReceive only show part of the message(if the length of the string is more than 5, it only show 5),i do not kow why.who can? tell me. thank you