IMAP settings · ionos.com · ionos.de · 1and1.com
IONOS IMAP settings
IONOS hosts mail for millions of domains under several brands and in several countries, which is why answers about "the IONOS server" disagree with each other. The documented host is imap.ionos.com; regional accounts can be served under a country domain instead, and the control panel always shows the one that belongs to your mailbox.
IMAP connection
- Server
- imap.ionos.com
- Port
- 993
- Encryption
- SSL/TLS
- Username
- full address
- Password
- the mailbox password
Sending, SMTP
- Server
- smtp.ionos.com
- Port
- 465
- Encryption
- SSL/TLS
Checked against the service's own documentation on 2026-09-15: it publishes no autoconfiguration file. Source: www.ionos.com, www.ionos.co.uk
What breaks here.
- Regional hosts exist alongside imap.ionos.com. If authentication fails with a password you are sure about, check the mailbox settings in the IONOS panel for the server it names.
- TLS 1.0 and 1.1 are no longer accepted. An old client that cannot do TLS 1.2 fails at the encryption stage, which looks like a connection problem rather than a client problem.
- The username is the full address, not the customer number you sign in to the panel with.
- A mailbox moved to Microsoft 365 through IONOS is a Microsoft 365 mailbox: its host is outlook.office365.com, and the IONOS hosts will not authenticate it.
Questions
The short answers
Which host do I use?
imap.ionos.com on port 993 with SSL/TLS, and smtp.ionos.com on 465 for sending. If your account is regional, the panel shows the exact server for your mailbox.
What is the username?
The full email address. The customer number is for the IONOS control panel, not for IMAP.
Why does my old mail program suddenly fail?
Most often because it only supports TLS 1.0 or 1.1, which IONOS has disabled. Updating the program fixes it; changing ports does not.
Can I migrate a whole IONOS mailbox elsewhere?
Yes — messages, folder tree, flags and dates transfer over IMAP, and the IONOS mailbox stays as it is until you delete it yourself.
Find out how big your mailbox is. It costs nothing.
Connect two servers, look at the size and decide. Or take the client and keep everything on your side.
Code on GitHub · built on imapsync · no sign-up