When generating an invoice -what does OOS - inactive mean?

Hi James74, 

This means that something on the invoice, such as the product/service or VAT code has been made inactive. This is common in cases where customers have migrated from QuickBooks Desktop and are selecting a VAT code that has migrated and is not compatible with QuickBooks Online. You can see the full QuickBooks Online VAT codes which you should be using here - these can be turned on/off within the VAT centre (Taxes > Edit VAT > Edit rates).

Please get back to us below if you have any Q's on this. 

Thanks!