Incremental Load in BU fails

I have followed this guide to set-up an Incremental load on a table in BU:
Incremental Loading in a Business Unit (BU) in TimeXtender Classic | Community

However, during the deploy i get an error:

Data source Incr Loads
Validation status: Valid
Message: OK

Staging Database ODX
Validation status: Valid
Message: OK

Table: Incr_Load
Validation status: Valid
Message: OK

Incremental Load
Validation status: Error
Message: Incremental load is not supported on this table.

Details:

Data source Incr Loads ...
TimeXtender.DataManager.UserErrorException

It says in the guide that:
 

When the option is enabled and the table is deployed, TimeXtender performs the following:

1. Initial Full Load: The system fully loads the table.
2. Setting content of the _I Table: This table records the largest incremental field value from the given load

I am attachig a video of where i get an error.
What am i doing wrong?