My team regularly leverages offline areas in FieldMaps for Enterprise. Every other week, someone will create a FieldMap that is correctly configured for offline use (all layers shown as offline-ready), but the FieldMap will fail to create offline areas.
We can identify which layer is causing the problem by systematically removing/re-adding layers and trying to create offline areas again, but that is a time-consuming and inefficient process, especially in a map with many layers.
Sometimes we can get additional insights into which layer is causing the failure by looking at the Server Logs, but that requires someone with administrative privileges to look into the problem.
It would save a lot of time if an offline area "failed" to be created and returned a useful error in the offline map GUI that identifies which feature/features are causing offline areas to fail. This would allow non-admin users to more effectively troubleshoot their own problems.
Ideally, the issues that are causing these offline areas to fail would be resolved instead, but I'd be happy to start by at least having more information to work from.