Use Sync History when you want to confirm whether a sync succeeded, partially succeeded, failed, or ended with no new data.
The Syncs tab lists each sync with its route, result, time, and per-category summaries.
The Categories tab lets you open one category such as Steps, Sleep, or Weight and review either recent body data or sync notes, depending on what that category supports.
If something still looks wrong, compare the affected category, date range, and most recent sync before you contact support.