Keep Alive: Should AcyMailing keep your SMTP Connection opened during the send Process? We recommend to turn ON this option. This option should be turned OFF only if you have problems. If you turn it OFF, AcyMailing will connect to your SMTP server, then send one e-mail, and then close the connection. It will need to reopen the connection with your SMTP server to send another e-mail so it may consume a lot of time whereas if you turn this option ON, AcyMailing will open the connection with the SMTP server once, send the whole batch of e-mails and then close the connection.