Email Settings for Online.de
Access your Online.de account from your macOS or Windows email client.
Email Settings for Online.de
Incoming Server - IMAP
Server: imap.1und1.de
Port: 993
Security: SSL/TLS
Username: Your full email address
Password: Your password
Outgoing Server - SMTP
Server: smtp.1und1.de
Port: 587
Security: STARTTLS
Username: Your full email address
Password: Your password