I have a workbench that has two ESRI Reprojectors that work fine when run in FME Desktop.
The first ESRI Reprojector projects from NAD_1983_CSRS_Teranet_Ontario_Lambert to NAD_1983_Teranet_Ontario_Lambert and uses a custom transformation that I created using documentation from our parcel supplier (Teranet). The second ESRI Reprojector reprojects from NAD_1983_Teranet_Ontario_Lambert to NAD_1983_UTM_Zone_17 and does not require a datum transformation.
I have copied the transformation file I created on my desktop pc to the server and put it in the same location:
C:\\Users\\Administrator\\AppData\\Roaming\\ESRI\\Desktop10.4\\ArcToolbox\\CustomTransformations
As well, I copied the grid shift file to C:\\Program Files (x86)\\ArcGIS\\Desktop10.4\\pedata\\ntv2\\canada as per the instructions provided by our parcel supplier (Teranet).
When I upload the workbench to FME Server and attempt to run the job in FME Server it stops almost immediately with the following error EsriReprojector: Reproject: Could not reproject the geometry of the preceding feature: Reprojector; Invalid reprojection parameters.
Installed ArcMap 10.4.1 and FME Server 2017.1.1 - Build 17650 - win64