When you send an invoice for approval, the contact linked to the job number must be active in Xero. If the contact is archived in Xero, you will get an error icon in Invoicing > Awaiting Approval alerting you that the contact must be un-archived before creating new invoices or credit notes.

To resolve the contact archive error:
- Go to Contacts > All contacts > Archived.

- Search for the archived contact and open it.
- Click Restore.

- Go to Invoicing > Awaiting Approval. The contact archiving error will now be resolved and you can approve the invoice.