Tcpclient break when sending the json

[JacksonLv]

I use the library to generate a Json and use a Spark Photon to send the Json to a client as a TCP Server.As first ,it runs great.But after a few time,the client could not get the json any more.
Here is my code:

#define MAX_CLIENT_NUM   3
// Server Port
TCPServer server = TCPServer(8888);
TCPClient client[MAX_CLIENT_NUM];
aJsonStream serial_stream(&Serial);

void setup()
{
   char addr[16];

    Serial.begin(115200);
    delay(5000);

    WiFi.on();
    WiFi.setCredentials(AP, PIN, WPA2);
    WiFi.connect();

    IPAddress localIP = WiFi.localIP();

    while (localIP[0] == 0)
    {
        localIP = WiFi.localIP();
        Serial.println("waiting for an IP address");
        delay(1000);
    }

    sprintf(addr, "%u.%u.%u.%u", localIP[0], localIP[1], localIP[2], localIP[3]);

    Serial.println(addr);

    server.begin();
}
void loop()
{

    aJsonObject *root = aJson.createObject();
    aJson.addItemToObject(root, "cmd", aJson.createItem("G"));
    aJson.addItemToObject(root, "pin", aJson.createItem(1));
    aJson.addItemToObject(root, "pinmode", aJson.createItem(1));
    aJson.addItemToObject(root, "data", aJson.createItem(999));
    Serial.print("Json_tx_string:  ");
    aJson.print(root, &serial_stream);
    Serial.println(); 
    for(uint8_t i = 0;i<MAX_CLIENT_NUM;i++)
    {
        if (client[i].connected())
        {
            Serial.println("Connected by TCP client.");
            client[i].println(aJson.print(root));                      
        }
        else
        {
            client[i] = server.available();
        }
    }
    aJson.deleteItem(root);
    delay(200);
}