It is when you enable you Uart - Dma you must enable UART isr. Wihout it the huart->gState will be in HAL_UART_STATE_BUSY_TX. You can debug it and check if it happens to you. (from)

void printUART(void){
    sprintf(txBufferUART,"test");
    if(HAL_UART_Transmit_DMA(&huart1, (uint8_t *)txBufferUART, strlen(txBufferUART)) != HAL_OK)
        Error_Handler();
}

void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)
{
  ;
}

void HAL_UART_TxHalfCpltCallback(UART_HandleTypeDef *huart)
{
  ;
}