problem with updating multiple fields on thingspeak channel simultaneously using nodemcu | ThingSpeak Projects | Forum

Hello friends,
I have started working on IoT projects recently. Plz help me in this regard.
I have written the following code to write/update the multiple data fields on Thingspeak channel simultaneously. But sometimes it updates all the fields and sometimes it updates only the first field. please I need help in this regard. I am working on college projects on IOT

#include ;

#include ;

#include ;

const char* ssid = "Computronics"; //Your Network SSID

const char* password = "asd941967"; //Your Network Password

WiFiClient client;

unsigned long myChannelNumber = 835361; //Your Channel Number (Without Brackets)

const char * myWriteAPIKey = "17DLAQVQ9UYVCGC4"; //Your Write API Key

void setup()

{

Serial.begin(9600);

delay(10);

// Connect to WiFi network

WiFi.begin(ssid, password);

ThingSpeak.begin(client);

}

void loop()

{

int val1 = 900; //Read Analog values and Store in val variable
int val2 = 1000;
int val3 = 500;
int val4 = 200;

ThingSpeak.writeField(myChannelNumber, 1,val1, myWriteAPIKey); //Update in ThingSpeak
ThingSpeak.writeField(myChannelNumber, 2,val2, myWriteAPIKey);
ThingSpeak.writeField(myChannelNumber, 3,val3, myWriteAPIKey); //Update in ThingSpeak
ThingSpeak.writeField(myChannelNumber, 4,val4, myWriteAPIKey);

delay(15000);

}

regards
Anita H.k