Can Collector for ArcGIS edit a feature service from a file geodatabase registered to an ArcGIS Server?

Note:
The functionalities of ArcGIS Collector, ArcGIS Explorer, and ArcGIS Tracker are now available in ArcGIS Field Maps. There are no new capabilities planned for these apps—all future updates will be focused on Field Maps. Migration is recommended. See ArcGIS Blog: Migrate to Field Maps for more information.

Collector for ArcGIS cannot make edits to a feature class in a file geodatabase that is registered to a server. To use ArcGIS Server feature services in Collector for ArcGIS, the feature services must come from an enterprise geodatabase.

If the intent is to only use the file geodatabase as source data, an alternative is to consume that data in ArcGIS for Desktop or ArcGIS Pro and publish the data as a hosted feature layer to Portal for ArcGIS or ArcGIS Online.

For more information on data supported in Collector for ArcGIS, see the following document: Supported data.