The data you publish to a sync-enabled feature service cannot include a relationship class that uses the ObjectID field as its primary key, and the data cannot contain an attachment based on an ObjectID. To use sync capability, relationship classes and attachments must be based on a GlobalID field.
Do one of the following:
- Use the Migrate Relationship Class geoprocessing tool to convert ObjectID-based relationship classes to GlobalID-based relationship classes.
- Disable attachments, add a GlobalID field to the dataset, and reenable attachments. As long as a GlobalID field is present, GlobalIDs will be used for the attachment relationship.
- Do not include the relationship classes in the sync-enabled feature service.