Hi. I've included the code below. I want to pause for 10 seconds in standby mode. The code works once and never returns. And there is no serious drop in Ammeter. What could I be doing wrong?

#include <string.h>
#include <stdio.h>
#define printf(...) HAL_UART_Transmit((UART_HandleTypeDef *)&hlpuart1, (uint8_t *)u_buf,\
		 sprintf((char*)u_buf,__VA_ARGS__), 0xFFFF);
uint8_t u_buf[256];
/* USER CODE BEGIN 2 */
 
 
 if (__HAL_PWR_GET_FLAG(PWR_FLAG_SB) != RESET)
 	 {
 	 	 __HAL_PWR_CLEAR_FLAG(PWR_FLAG_SB); // clear the flag
 
 	 	 /** display the string **/
 	 printf("Wakeup from the STANDBY MODE\r\n");
 
 	 	 /** Blink the LED **/
 	 	 for (int i=0; i<20; i++)
 	 	 {
 	 		 HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);
 	 		 HAL_Delay(200);
 	 	 }
 
 	 	 /** Disable the WWAKEUP PIN **/
 	 	 HAL_PWR_DisableWakeUpPin(PWR_WAKEUP_PIN1); // disable PA0
 
 	 	 /** Deactivate the RTC wakeup **/
 	 	 HAL_RTCEx_DeactivateWakeUpTimer(&hrtc);
 	 }
 
 
 	 /** Now enter the standby mode **/
 	 /* Clear the WU FLAG */
 	 __HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);
 
 	 /* clear the RTC Wake UP (WU) flag */
 	 __HAL_RTC_WAKEUPTIMER_CLEAR_FLAG(&hrtc, RTC_FLAG_WUTF);
 
 	 /* Display the string */
 	 printf("About to enter the STANDBY MODE\r\n");
 	 /* Blink the LED */
 	 for (int i=0; i<5; i++)
 	 {
 	 	 HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);
 	 	 HAL_Delay(750);
 	 }
 
 	 /* Enable the WAKEUP PIN */
 	 HAL_PWR_EnableWakeUpPin(PWR_WAKEUP_PIN1);
 
 	 /* enable the RTC Wakeup */
 	 /* RTC Wake-up Interrupt Generation:
 	 Wake-up Time Base = (RTC_WAKEUPCLOCK_RTCCLK_DIV /(LSI))
 	 ==> WakeUpCounter = Wake-up Time / Wake-up Time Base
 
 	 To configure the wake up timer to 5s the WakeUpCounter is set to 0x2710:
 	 RTC_WAKEUPCLOCK_RTCCLK_DIV = RTCCLK_Div16 = 16
 	 Wake-up Time Base = 16 /(32KHz) = 0.0005 seconds
 	 ==> WakeUpCounter = ~5s/0.0005s = 20000 = 0x2710
 	 */
 	 if (HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, 0x5F46, RTC_WAKEUPCLOCK_RTCCLK_DIV16) != HAL_OK)
 	 {
 	 Error_Handler();
 	 }
 
 	 /* one last string to be sure */
 	 printf("STANDBY MODE is ON\r\n");
 	 /* Finally enter the standby mode */
 	 HAL_PWR_EnterSTANDBYMode();
/* USER CODE END 2 */
 
 /* Infinite loop */
 /* USER CODE BEGIN WHILE */
 while (1)
 {
 /* USER CODE END WHILE */
 
 /* USER CODE BEGIN 3 */
	 
 
 
 }