STMF103 usb VCOM usb not initialized with "USB_DEVICE" library

[Dioswilson]

I am using a STM32F103 and having issues to make an USB application.

I generated the project using CubeMX and I am not being able to transmitt a message.
Here is the configuration:

Main is like this (It is C++ in case it matters):

int main(void) {
    HAL_Init();
    SystemClock_Config();

    MX_USB_DEVICE_Init();

    while (true) {
        HAL_Delay(100);
        volatile uint8_t result = CDC_Transmit_FS((uint8_t*) secondLine, strlen(secondLine));
        if (result != USBD_OK) {
        }
    }
}

 After inspecting in debug mode the CDC_Transmit_FS function I saw it was returning "USBD_BUSY":

uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len)
{
  uint8_t result = USBD_OK;
  /* USER CODE BEGIN 7 */
      USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef*)hUsbDeviceFS.pClassData;
  if (hcdc->TxState != 0){
    return USBD_BUSY;
  }
  USBD_CDC_SetTxBuffer(&hUsbDeviceFS, Buf, Len);
  result = USBD_CDC_TransmitPacket(&hUsbDeviceFS);
  /* USER CODE END 7 */
  return result;
}

I saw that hcdc structure is NULL and that is why function is returning USBD_BUSY.
Also when connected to Windows10 computer, no device is detected.

Just in case the (autogenerated) MX_USB_DEVICE_Init function looks like this:

/**
  * Init USB device Library, add supported class and start the library
  * @retval None
  */
void MX_USB_DEVICE_Init(void)
{
  /* USER CODE BEGIN USB_DEVICE_Init_PreTreatment */

  /* USER CODE END USB_DEVICE_Init_PreTreatment */

  /* Init Device Library, add supported class and start the library. */
  if (USBD_Init(&hUsbDeviceFS, &FS_Desc, DEVICE_FS) != USBD_OK)
  {
    Error_Handler();
  }
  if (USBD_RegisterClass(&hUsbDeviceFS, &USBD_CDC) != USBD_OK)
  {
    Error_Handler();
  }
  if (USBD_CDC_RegisterInterface(&hUsbDeviceFS, &USBD_Interface_fops_FS) != USBD_OK)
  {
    Error_Handler();
  }
  if (USBD_Start(&hUsbDeviceFS) != USBD_OK)
  {
    Error_Handler();
  }

  /* USER CODE BEGIN USB_DEVICE_Init_PostTreatment */

  /* USER CODE END USB_DEVICE_Init_PostTreatment */
}