One of the frustrating parts of managing SharePoint lists is the distinction between the internal ID and the name of site columns. SharePoint generally uses the internal ID for search queries, CAML queries, REST API calls, CSOM API calls, etc. and they are not always the same as what you see on the list settings.
Here is a custom list I created for storing promotional content:
SharePoint’s internal ID for title is “Title”. However, the internal ID for Description is actually “RoutingRuleDescription”. The internal ID for “Page Image” is actually “PublishingPageImage”.
There is an easy way to find this out – just look at the URL of the columns on this page. For example, the URL for the Description column is:
The Field Parameter at the end of the URL is the internal ID for that site column!