Thingspeak probleme

Hallo zusammen,

nach dem einfügen des Thingspeak Teiles in mein Projekt blink jetzt die LED am Pin 13 aber wieso und Daten bekomme ich auch nicht in das Thingspeak geschrieben, hat wer eine Lösung oder Idee?
Die Daten aus dem Solarregler bekomme ich ausgelesen und via RS auch angezeigt.
verwendet wird ein Arduino Mega 2560 und ETH Shield

#include <ThingSpeak.h>
#include <ModbusMaster.h> //Modbus für Traver3210A
#include <Ethernet.h> //Netzwerk
#include <SPI.h> // SPI für Ethernetboard



#define MAX485_DE      17 //freigabe MAX485
#define MAX485_RE_NEG  16 //freigabe MAX485

byte mac[] = {0x00, 0x07, 0x7E, 0x00, 0x00, 0xED};
EthernetClient client;
IPAddress ip(192, 168, 1, 10);
ModbusMaster node; // instantiate ModbusMaster
//Thingspeak einstellungen
unsigned long myChannelNumber = 123456;
const char * myWriteAPIKey = "XXXXXXXXXXX";


void preTransmission()
{
  digitalWrite(MAX485_RE_NEG, 1);
  digitalWrite(MAX485_DE, 1);
}

void postTransmission()
{
  digitalWrite(MAX485_RE_NEG, 0);
  digitalWrite(MAX485_DE, 0);
}

void setup()
{

  Ethernet.begin(mac, ip);  // initialize Ethernet device

  pinMode(MAX485_RE_NEG, OUTPUT);
  pinMode(MAX485_DE, OUTPUT);
  // Init in receive mode
  digitalWrite(MAX485_RE_NEG, 0);
  digitalWrite(MAX485_DE, 0);


  Serial.begin(9600);      // RS232 communication @ 9600 baud
  Serial1.begin(115200);  // Modbus communication @ 115200 baud


  node.begin(1, Serial1); // Modbus slave ID 1
  // Callbacks allow us to configure the RS485 transceiver correctly
  node.preTransmission(preTransmission);
  node.postTransmission(postTransmission);
    delay(5000);
  
}

bool state = true;

void loop()
{
  uint8_t result;
  uint16_t data[6];

  // Toggle the coil at address 0x0003 (Manual Load Control)
  result = node.writeSingleCoil(0x0003, state);
  state = !state;

  // Read 16 registers starting at 0x3100)
  result = node.readInputRegisters(0x3100, 16);
  if (result == node.ku8MBSuccess)
  {

    float U_Solar = (node.getResponseBuffer(0x00) / 100.0f); // Spannung der Solarzellen
    float I_Solar = (node.getResponseBuffer(0x01) / 100.0f); //Strom der Solarzellen
    float U_Bat = (node.getResponseBuffer(0x04) / 100.0f); //Batteriespannung
    float I_Lade = (node.getResponseBuffer(0x05) / 100.0f); //Ladestrom Batterie
    float I_Last = (node.getResponseBuffer(0x0D) / 100.0f); // Laststrom Batterie
    float LastWatt = (node.getResponseBuffer(0x0E) / 100.0f); // Last Watt
    float BatterieTamp = (node.getResponseBuffer(0x10) / 100.0f); // Batterie Temperatur
    float BatterieStrom = ((node.getResponseBuffer(0x05) / 100.0f) - (node.getResponseBuffer(0x0D) / 100.0f)); // Ladestrom - Laststrom
    Serial.print("Solarspannung: ");
    Serial.println (U_Solar );
    Serial.print("Solarstrom: ");
    Serial.println (I_Solar );
    Serial.print("Batteriespannung: ");
    Serial.println(U_Bat );
    Serial.print("Ladestrom: ");
    Serial.println(I_Lade );
    Serial.print("Laststrom: ");
    Serial.println(I_Last);
    Serial.print("Last Watt: ");
    Serial.println(LastWatt);
    Serial.print("Batterie Temp: ");
    Serial.println(BatterieTamp);
    Serial.print("Batteriestrom: ");
    Serial.println (BatterieStrom);
    ThingSpeak.setField(1,U_Bat);
   // ThingSpeak.setField(2,BatterieStrom);
    //ThingSpeak.setField(3,U_Sollar);
    //ThingSpeak.setField(4,I_Lade);
    //ThingSpeak.setField(5,I_Last); 
    ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey); //Daten schreiben

  }

  delay(1000);
}


Gruß Markus