Read the QuickBooks sync activity log

Do this

1. 1

   Settings → QuickBooks → Sync activity

   Filter by record type and status (synced, failed, pending).

2. 2

   Read the reason

   Failures say what to fix: an unmapped tax rate, a missing item mapping, a customer that no longer exists in QuickBooks, an expired connection.

3. 3

   Fix and Retry

   Correct the mapping or record, then Retry the row. Settle all retries every failed row after a broad fix and has a realistic timeout for large batches.