If you have noticed the 'Recipient could not be found' message when trying to send out an invoice, it means that there is something wrong with the sending settings or the recipient's email address. Let's take a look at the most common reasons for this issue:
First thing you need to do when getting the 'Recipient could not be found' error message is to check your billing settings. If you haven't enabled the 'We'll email invoices' under Billing/Settings, the system will consider that there is no recipient for this message. Either company or billing person or both should be enabled, in order for the message to be successfully sent.
If you have enabled the above-mentioned 'We'll email invoices' option but you are still getting the error message, it means that the recipient (company or billing person or both) does not have an email address. You have to open the Company/Billing Person profile and add an email address for them so you can successfully send the invoice.