When emailing Invoices from the Invoices Page/Tab, you may have run into an “HTTP error 406” message. We recently re-wrote some code for Invoices and that re-write prevented us from showing a green success message when you attempted to send an Invoice. Instead, we’d show the error .
This has been fixed and you should no longer see the error come up. Just note any Invoices that were sent during that timeframe were successful so no Invoices are required to be re-sent .