STM32 Keil - Can not access target - stm32

Question

I'm trying to debug my stm32f407 project in Keil but I get the message "cannot access target shutting down debug session ". I'm trying to work with the DHT11 sensor and I want to show the result on the LCD. but I can't debug the code and can't figure out what is the problem.
for the dht11 sensor, I used the guidness in
https://controllerstech.com/using-dht11-sensor-with-stm32/
I can program the MCU and run the code, the problem is only in debugging.
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "adc.h"
#include "i2c.h"
#include "tim.h"
#include "usart.h"
#include "gpio.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "tm_stm32_hd44780.h"
#include "stdio.h"
#include "string.h"
#include "bh1750.h"
#include "DHT.h"
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
/* USER CODE END PTD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN PV */
char DM[35]="temp is: ";
char RT[35]="humidity is: ";
char ch[10]="10";
uint8_t TEMP;
uint8_t RH;
//strncat(tara, &ch, 1);
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
#define DHT_H_11
DHT_DataTypedef DHT11_Data;
float Temperature, Humidity;
#define DHT11_PORT GPIOA
#define DHT11_PIN GPIO_PIN_1
/* USER CODE END 0 */
/**
* #brief The application entry point.
* #retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_ADC1_Init();
MX_I2C1_Init();
MX_I2C2_Init();
MX_TIM6_Init();
MX_USART1_UART_Init();
MX_USART2_UART_Init();
MX_USART3_UART_Init();
/* USER CODE BEGIN 2 */
TM_HD44780_Init(16,2);
TM_HD44780_Puts(0,0,(char*)DM);
TM_HD44780_Puts(10,10,(char*)TEMP);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
DHT_GetData(&DHT11_Data);
Temperature = DHT11_Data.Temperature;
Humidity = DHT11_Data.Humidity;
HAL_Delay(3000);
}
Temperature=(char) TEMP;
Humidity= (char) RH;
HAL_Delay(1000);
TM_HD44780_Puts(10,10,(char*)TEMP);
TM_HD44780_Puts(0,0,"STM32 <3");
/* USER CODE END 3 */
}