Issue while binding the output of the service to the dropdown widget

I have an issue while binding the output of my service to the dropdown widget.

This is my service below when I execute it by clicking on 'play' button it gives me my desired output.

let alldata = Things["Paitent_Data_Table"].GetDataTableEntries();
let params = {
t: alldata /* INFOTABLE */,
columns: "Paitent_Name" /* STRING */
};

// result: INFOTABLE
result = Resources["InfoTableFunctions"].Distinct(params);

but when I add this service to the 'data tab' in mashup builder and when I expand all data tab of this service I am not getting data over there. but this is happening only for this service the other services are working properly.