There are various methods of connecting to mailboxes on our platform. We always recommend IMAP as that helps keep messages in sync between various devices and our webmail system. This is our recommended configuration for Thunderbird mail clients. Incoming Server (“Account Settings” > “Server Settings”) Server Name: imap.stackmail.comUsername: Your e-mail addressPort: 993Connection security: SSL/TLSAuthentication method: 'Normal password' Outgoing Server (SMTP) Server Name: smtp.stackmail.comPort: 587Connection Security: STARTTLS Authentication method: 'Normal password'Username: Your e-mail address If you choose to use domain-branded server names, such as mail.your-domain or imap.your-domain, the secure connection may throw a certificate warning due to a common name mismatch. This can be safely trusted and your connection will remain secure.