Popup with related tables

I'm finding difficulties displaying values of a related table in a popup window.

Esri said that at version 3.10 and above, popup templates can include fields from related tables using the syntax (relationships/relationship_id/field_name). I tried this syntax but it is not working.

I also checked the sample in this page: https://developers.arcgis.com/javascript/jssamples/popup_relatedrecords.html

It uses the same syntax to call a related field but it only works under mediaInfos, which is strange!

Please help!