I am having issues updating a feature service with Safe FME. I looked up the example model and as far as I can tell I am following it. It seems to be running most of the model and throws an error as it starts trying to update the Feature Service. I am not sure what the issue is. I set the Feature Layer to allow edits. I have the reader for the ArcGIS Feature Layer and the Reader for the shapefile source, also the FeatureMerger to add the FID Field to the update table. LOG: http://pastebin.com/U1Hu06GS
I was running into similar situation attempting to write to AGOL hosted tables. Was getting error 403 (You do not have permissions to access this resource or perform this operation). I tried about every permutation of connection configuration I could think of, but no love. However, when I added a Reader to the AGOL feature service, it started working, even though Reader is not really involved in workflow.
Whats interesting is there actually is a bug for this with Arc online: