I have the same problem. I also tried fgets() with the same result. Does anybody know the reason for that?

This is the code:

#include <stdio.h>
#include "freeRTOS/freeRTOS.h"
#include "FreeRTOS/task.h"
#include "driver/gpio.h"
#include "sdkconfig.h"
#include "driver/uart.h"

#define TX_PORT_NUM ...