Xero: How do I resolve the "RECBADDEBT Xero error"?

If you're seeing this Xero error, the issue is that the RECBADDEBT account that's created for write-off invoices is of account type "EXPENSE" and your TAX001 can work with Accounts of the following "Account Type" in Xero: 

assets: true

equity: true

expenses: false

liabilities: true

revenue: true

What you can do is change the drop down "Account Type" for the RECBADDEBT (in Xero) account to be of one of the types that isn't expenses (for example, changing to liabilities will fix it and allow associated invoices to sync) then the invoices should sync over.