Freelance service, dont pay vat. My first invoice is not sending due to a ‘delivery error’

Hello and welcome to the Community, rachel-childs-bt

We're not aware of any current delivery errors when sending invoices in QuickBooks Online. 

To check for any browser issue that may be causing this, please first try sending the invoice by signing into QuickBooks through a different web browser or private browsing window (on Chrome, press Ctrl + Shift + n at once to open). 

If the invoice sends successfully from there, consider clearing the cache and cookies on your normal web browser so that you can continue to access QuickBooks there. 

Please get back in touch below if these steps do not resolve the error. Thank you!