Bluetooth LE not able to write

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Hi, I am facing an issue where I am not able to Write data to a characteristic. When using the nrf Connect app it works just fine. I am using an esp32 with the ArduinoBLE Libary. My blocks:

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And my code looks as follows:

#include <ArduinoBLE.h>

BLEService ledService("3c122611-50e5-4003-9d6e-f8e7cb584001"); // Bluetooth® Low Energy LED Service

// Bluetooth® Low Energy LED Switch Characteristic - custom 128-bit UUID, read and writable by central
BLEByteCharacteristic switchCharacteristic("be3b3270-8449-4579-abbb-0301c2dae3c2", BLERead | BLEWrite);

const int ledPin = 2; // pin to use for the LED

void setup() {
  Serial.begin(9600);
  while (!Serial);

  // set LED pin to output mode
  pinMode(ledPin, OUTPUT);

  // begin initialization
  if (!BLE.begin()) {
    Serial.println("starting Bluetooth® Low Energy module failed!");

    while (1);
  }

  // set advertised local name and service UUID:
  BLE.setLocalName("LED");
  BLE.setAdvertisedService(ledService);

  // add the characteristic to the service
  ledService.addCharacteristic(switchCharacteristic);

  // add service
  BLE.addService(ledService);

  // set the initial value for the characeristic:
  switchCharacteristic.writeValue(1);

  // start advertising
  BLE.advertise();

  Serial.println("BLE LED Peripheral");
}

void loop() {
  // listen for Bluetooth® Low Energy peripherals to connect:
  BLEDevice central = BLE.central();

  // if a central is connected to peripheral:
  if (central) {
    Serial.print("Connected to central: ");
    // print the central's MAC address:
    Serial.println(central.address());

    // while the central is still connected to peripheral:
    while (central.connected()) {
      // if the remote device wrote to the characteristic,
      // use the value to control the LED:
      if (switchCharacteristic.written()) {
        Serial.println("Got data!");
        if (switchCharacteristic.value()) {   // any value other than 0
          Serial.println("LED on");
          digitalWrite(ledPin, HIGH);         // will turn the LED on
        } else {                              // a 0 value
          Serial.println("LED off");
          digitalWrite(ledPin, LOW);          // will turn the LED off
        }
      }
    }

    // when the central disconnects, print it out:
    Serial.print(F("Disconnected from central: "));
    Serial.println(central.address());
  }
}

What am I doing wrong?