The parameter keyname identifies the field to be queried on. Note that you must use the technical field name (not the alias name specified in the ArcMap document or in the geodatabase).
If e.g. the field alias is ‘City Name’ (this value gets displayed in WebOffice author) then open the Layer properties dialog in ArcMap and get the technical field name (e.g. Name = CITY_NAME) there. For this example use keyname=CITY_NAME as parameter.

Field Name - Alias Name of Geodatabase

Technical Fieldname