SYNC999: Sync unexpected
What this means
Syncing hit an unexpected problem.
Sales already recorded on this device are safe. Check the log first (see Troubleshoot): this may retry automatically, or — if a write never reached the queue — need re-entering. If this code keeps appearing, export diagnostics and contact support.
Your data
If your entry was captured, it is safe on this device and has not yet reached your store; if the log shows the write failed before it was queued (see Troubleshoot step 2), re-enter it. If this persists, export diagnostics and contact WCPOS support.
Troubleshoot
- Do not assume this code will retry. Expand the log entry first: if it confirms the mutation was already queued, WCPOS retries automatically, so leave it open and let the queue drain.
- If the error says the engine resident is missing or the write failed before a mutation ID was returned, nothing was queued — return to that record or order and save it again.
- Expand the log entry and note the event code and any serverCode: a 999 code means the specific cause has no dedicated code yet, so this context is exactly what support needs.
- If the code keeps appearing, use Copy debug info and contact support — reporting it is how the specific code gets added.