Xero sync error: Another invoice with this invoice number already exists in Xero – Support

Why the sync error occurs

This error occurs when an invoice can't sync to Xero because the invoice number already exists in Xero.

If this is a new invoice, edit the invoice number to one that doesn't already exist in Xero and sync again
If the invoice was also manually created in Xero, contact Customer Support to link the invoices
- In order for the sync to work properly, bills should be created in either Xero or Bill.com and synced to the other system