Why the sync error occurs
This error occurs when a deleted account is trying to sync to QuickBooks Online from Bill.com, and the account is set as an Opening Balance Equity account in QuickBooks Online. QuickBooks Online doesn't allow Opening Balance Equity accounts to be deleted.
How to fix the sync error
The Opening Balance Equity account can't be deleted or edited in QuickBooks Online. The only options are to reactivate the deleted account in Bill.com or to contact Customer Support to clear the error.