HELP! GoupBy Configuration with flow variables

I am trying to configure the [GroupBy](https://hub.knime.com/knime/extensions/org.knime.features.base/latest/org.knime.base.node.preproc.groupby.GroupByNodeFactory) node with flow variables.

As can be seen in the screenshot below:

GroupBy Columns:

1. Added Include List.

2. Exclude List

In Aggregation Section:

1. I added the column Name List.

2. aggregationMethod is Maximize for every columns

3. inclMissingVals is true for every column

4. *ColumnTypes: I have no idea what I should send.*

I am getting the following message:

I need help; what am I doing wrong, or what data or kind of data does it require?

It would be helpful if anyone could demo it in the workflow with any data.