Default Emailaddress: This address is used to send all system emails to.
SMTP-Server: This is your Mailserver for outgoing mail (often called SMTP server). Mostly these servers have names like mail.YOURDOMAIN.de or smtp.YOURDOMAIN.de. Please ask your mailprovider for the correct name.
Portnumber: The Port number at which the mailserver accepts ingoing email. Mostly the Port number is 25 or 587. Please ask your mail provider for the correct port.
Use encrypted link: Most mailservers need or provide excrypted connections. Please ask your provider if your mailserver supports encryption (look for the key word STARTTLS).
Authentification: Most mailservers use authentification nowadays. Please ask your mail provider for the correct username and password.
SMTP Username: Username for your mailserver.
SMTP Password: Password for your mailserver.