If the Failed to connect to SMTP server error message is received while attempting to send e-mails. it can mean one of two things:
1) SMTP Settings are faulty. If your e-mail settings have not been updated since the last time you sent an e-mail, it is unlikely that the problem lies with your e-mail settings. If this is the first time you are trying to send e-mails from QuickEasy then the problem is likely related to your e-mail settings - especially if you are able to send e-mail from another mail client. The Staff/User SMTP settings in QuickEasy include:
2) There is a problem with the SMTP Server or the server is refusing your connection in which case you need to contact your internet service provider (ISP) for assistance.
The following link explains the difference between SSL, TLS and STARTTLS.