We have a couple offline Field Maps tailored for staff. ALL layers within the offline web maps are ArcGIS Online hosted layers with sync enabled.
Recently turned on sync / offline capabilities for a core layer for our organization. This layer is NOT hosted on AGOL, rather it is published to Portal and shared as an item using rest service URL to AGOL. Nothing else has changed in the map other than the addition of that service, however, when trying to download an offline map area, it gives a "Download failed" error fairly quickly. Is there an issue with offline mapping when referencing services from Portal? What could the solution be?
Reviewing the logs, it looks like the error is "Failed to create replica" and perhaps something with the token. It also says unknown error occurred when downloading map. Some known issues with the error above has to do with "move edits to base" checked, which ours is not. Our data is traditional versioned.