Get error 66, when try to make labview program communicate with arduino uno+ wifi shield.

[100148X]

I have a sever VI, keep sending data use TCP VIs. The client side is my arduino board (uno+ wifi shield), which can receive data wirelessly. I run both, they can successfully communicate once. At the 2nd time, the sever VI will close itself, because TCP write VI gets error 66. In VI server, I have allowed access of localhost, and IP address of my arduino.

[100148X]

[100148X]

Actually, they can communicate not only once, sometimes the VI can pass data several rounds, but suddenly the error 66 appears in TCP write, the loop will stop. And if I rerun the program, things happens again. can anybody tell me why the error come out? Thanks