Field help (NCSPROCAU) 

Use this field to identify the probable or possible cause of this incident. This field is mandatory. Your suggested reason should reflect what you subsequently add to the free-format Additional information (field NCSDES) field as the information will be used to help establish what the root cause of this incident might be.

The default code and the list of probable causes is defined in Miscellaneous table 804 - Probable cause.