Xero Error: Invoice not of valid status for modification

Issue

When syncing to Xero the error Invoice not of valid status for modification may occur.  

This error is caused when there is a duplicate invoice/bill number, or reference that already exists within Xero.

Resolution

Reference Number:

1. Check the Reference number in Xero to see if an existing Invoice/Bill already uses this Reference number
2. If so, Update the reference number in your Tradify Invoice to something unique

Bills:

1. Check Xero if a Bill has the same number (Check for voided bills also)
2. If so, select "Copy Bill" in Tradify to create a new bill with a new number

Invoices:

1. Check in Xero if an Invoice has the same number (Check for voided Invoices also)
2. If so, Update your next number sequence to your next unique number
3. Use the Copy Invoice from the Options menu to create a new invoice with a unique number
4. Consider changing your Xero integration settings to use Xero numbering sequence to avoid the same issue in the future.  

Additional Information

See this page on how to update your Xero integration settings: How To Integrate Your Tradify Account With Xero