@trunganhvu welcome to the KNIME forum. I think you will have to set your string variable as a workflow variable instead of a string configuration.
Under KNIME 5.x to do this you will have to switch to the older GUI. More details here:
@trunganhvu welcome to the KNIME forum. I think you will have to set your string variable as a workflow variable instead of a string configuration.
Under KNIME 5.x to do this you will have to switch to the older GUI. More details here: