In some instances it may be necessary to override a Xero sync error, this may be to remove from future reporting, due to ledger lock, or you have confirmed all the data is correctly captured in Xero, so there is a manual update option. This will remove the connection from Xero and if any future updates are made, the sync error icon will reappear.
To manually update the sync issue, open the Invoice to view all the details, scroll to the base where you will see the red Xero sync icon.
If you are unable to resolve the error, click Manual Update, you will be prompted by a pop-up to confirm you are removing the sync error from the invoice, click Continue.

