Why the Sync Error occurs
This error occurs when an account is deleted in Bill.com and the deletion is trying to sync to QuickBooks Online (QBO), but the account is set as the Retained Earnings account in QBO.
How to Fix the Sync Error
The Retained Earnings account cannot be deleted or edited in QBO. The only options are to reactivate the deleted account in Bill.com or to contact Customer Support to request that the error is cleared.