The short version: Excel (using Maps for Office) can see our internal geocoding services, which are exposed as Geocoding Utility Services through ArcGIS Online, but it never actually calls them with the data to be geocoded.
Now more detail:
We have a few geocoding services running on our internal ArcGIS for Server servers (behind our firewall). These services are exposed to ArcGIS Online and shared with all members of our organization. These locators work fine in our ArcGIS Online maps and apps. However, the locators are not called in Excel with the "Add Excel Data" tool. The locators are visible and can be selected and the user can even specify which columns belong to which parameters for the service and the service acts like it is running, but it always returns 0 results.
Watching the calls in Fiddler shows that Excel interrogates the correct internal REST endpoint to get the parameters of the selected locator, but no call is ever made to the internal geocoding service with the actual data to be geocoded.
I have seen a number of somewhat related posts but no resolutions. Anyone have a similar experience, or is anyone successfully utilizing local geocoding services from within Maps for Office?
The option "Allow Batch Geocoding" for our services is grayed out in the ArcGIS Online "Utility Services" configuration area. This is the path I am pursuing at the moment.