stm32f030f4p6 HAL_UART_Receive dont work

I'm using stm32f030f4p6. The system clock frequency is 8mhz. uart1 setting 9600, n, 8.1. I am using the following program code. wotchdog stm32f030f4p6 uart is running smoothly when I send 18 123456123456123456 characters from my computer serial port program in 100msn intervals. But the number of characters I sent is 18 instead of 18 hours, uart hangs. I would like to ask why this can happen. keil arm software v5 . watchdog is pasife.

while(1){

HAL_UART_Receive(&huart1,timeRx,1,HAL_MAX_DELAY);

HAL_UART_Transmit(&huart1,timeRx,1,HAL_MAX_DELAY);

}