While emailing multiple invoices from Posted Sales Invoices page,there might be an error after emailing half of the invoices. Though we can see errors in Job Queue Log Entries, we don't know which invoices are sent and which invoices are not sent due to errors. Client will not know who received the email until their customers compaint them that they didn't receive any invoices. It would be helpful if there is a detailed log about this information with Customer number/Invoice number