Invoices are being marked 'delivery issue' by QB. They have always gone through ok, so this is new. Copies come to me ok, but not to customers. Advice?

Hello Rex10, 

Welcome to the Community page, 

we are aware of invoices not sending to customers can you please reach out to our team on chat and quote this inv for them to add you onto it INV-69394 so that you then can receive any updates on the issue to your email address.