IONOS SMTP Settings
European host, formerly 1&1, whose mail servers change hostname with your country.
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Outgoing mail (SMTP)
SMTP server
smtp.ionos.com
Port. STARTTLS
587
Port. SSL/TLS
465
Security
SSL/TLS on 465 (recommended) or STARTTLS on 587.
Incoming mail (IMAP)
IMAP server
imap.ionos.com
Port. SSL/TLS
993
Incoming mail (POP3)
POP3 server
pop.ionos.com
Port. SSL/TLS
995
Sending limits & login
Daily send limit
Per-plan hourly and daily send limits apply.
Authentication
Sign in with your full email address and mailbox password, with outgoing authentication switched on.
App password
No app password. Set the mailbox password in your IONOS control panel.
European customers use the .de hostnames (smtp.ionos.de and so on). Legacy 1&1 names like imap.1and1.com should be updated to the ionos ones.
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IONOS SMTP, IMAP and POP3 settings
IONOS is the German host that used to trade as 1&1, and its mail servers carry the country domain you signed up under: imap.ionos.com in the United States, imap.ionos.co.uk in Britain, smtp.ionos.de in Germany. New mailboxes are throttled by age, starting at 50 messages an hour and only reaching 500 after 30 days. Since 29 January 2024 the From address has to sit on the same domain as the mailbox you log in with.
For incoming mail, use the IMAP server imap.ionos.com on port 993, or POP3 at pop.ionos.com on port 995. Pick the exact values from the tool above and copy them straight into your mail client.
Checked against IONOS's own documentation: ionos.com, ionos.co.uk. Ports and limits change, so check there too if something will not connect.
IONOS settings at a glance
One card with every server and port on it. Right click to save it, or share the page and this is the preview people see.
What to enter as your IONOS username and password
Wrong credentials, not a wrong port, are the usual reason a IONOS connection fails. These are the exact values to type.
Your full email address, for example you@yourdomain.com
The mailbox password you set under the Email tile in the IONOS panel, not your IONOS customer account password
Get your email passwordHow to set up IONOS in a mail client
The exact path through IONOS's own settings, in order.
- 1
Create the mailbox and set its password
Log in to your IONOS account and open the Email tile to create the address and set the password. A forwarding-only address has no mailbox behind it and cannot be added to a mail client.
- 2
Pick the hostname that matches your country contract
US contracts use imap.ionos.com, pop.ionos.com and smtp.ionos.com. UK contracts use imap.ionos.co.uk, pop.ionos.co.uk and smtp.ionos.co.uk. German contracts use smtp.ionos.de.
- 3
Set the incoming server
IMAP on port 993 with SSL/TLS, or POP3 on port 995 with SSL/TLS. IONOS recommends IMAP.
- 4
Set the outgoing server
SMTP on port 465 with SSL/TLS, or port 587 with STARTTLS if your network blocks 465. Turn outgoing authentication on and switch Secure Password Authentication off.
- 5
Confirm the client supports TLS 1.2
IONOS requires TLS 1.2 or higher for IMAP, POP3 and SMTP, and tells you to check your program's documentation rather than publishing a list of compatible operating systems.
What IONOS looks like filled in
Every mail client asks for the same handful of fields. Here they are with IONOS's values already in place.
Account settings: IONOS
Server
smtp.ionos.comPort
465Encryption
SSL/TLSAuthentication
RequiredUsername
Your full email address, for example you@yourdomain.comPassword
The mailbox password you set under the Email tile in the IONOS panel, not your IONOS customer account passwordServer
imap.ionos.comPort
993Encryption
SSL/TLSAn illustration of the fields, not a screenshot of any one app. Field names differ slightly between Outlook, Apple Mail and Thunderbird; the values do not.
IONOS SMTP settings in Thunderbird
The outgoing server dialog with IONOS's details entered. Outlook and Apple Mail ask for the same four things under slightly different names.
Which port should you use for IONOS?
SSL/TLS on 465 (recommended) or STARTTLS on 587.
STARTTLS
Starts as a plain connection, then upgrades to an encrypted one. The modern standard for sending.
SSL/TLS
Encrypted from the first byte. Widely supported and a good choice when 587 is blocked.
Plain SMTP
Meant for server-to-server relay. Home networks and cloud hosts block it, so do not use it to send from a client.
Why your IONOS connection is failing
The failures people actually hit with IONOS, and what fixes each one.
IONOS ramps new Mail Basic and Mail Business mailboxes by age: 50 messages an hour for the first 7 days, 100 to day 14, 400 to day 30, then 500. Wait out the hour, or wait out the ramp.
Since 29 January 2024 IONOS only accepts a sender address on the same email domain as the mailbox that authenticated. Change the plugin's From address to that mailbox's own domain.
IONOS requires TLS 1.2 or higher. A client or operating system that cannot negotiate TLS 1.2 will not connect on any port. Update the client or the operating system.
IONOS tells you to check first whether an Autodiscover record exists in the domain's DNS. Add the record, or set the account up manually with the hostnames and ports above.
IONOS forwarding addresses have no mailbox, so there is nothing for IMAP or POP to open. Convert it to a real mailbox in the panel first.
IONOS sending limits
The hourly rate rises with the age of the mailbox; storage is 2 GB or 100,000 emails on Mail Basic and 50 GB or 500,000 emails on Mail Business, and a full mailbox stops accepting incoming mail. IONOS-hosted Exchange is metered differently again, at 1 to 10 emails a minute over IMAP/POP3 by mailbox age.
Per hour
50 emails an hour in the first 7 days, 100 to day 14, 400 to day 30, then 500 (Mail Basic and Mail Business)
Max attachment
70 MB per attachment on Mail Basic and Mail Business; 100 MB on IONOS-hosted Microsoft Exchange
IONOS servers by region and plan
IONOS does not use one set of hostnames everywhere. Match the row to your account.
| Region or plan | SMTP | IMAP | POP3 |
|---|---|---|---|
| United States (ionos.com) | smtp.ionos.com | imap.ionos.com | pop.ionos.com |
| United Kingdom (ionos.co.uk) | smtp.ionos.co.uk | imap.ionos.co.uk | pop.ionos.co.uk |
| Germany (ionos.de) | smtp.ionos.de | Not applicable | Not applicable |
IONOS quirks by mail client
Outlook
IONOS says to leave 'Logon using Secure Password Authentication (SPA)' unticked, and to tick 'My outgoing server (SMTP) requires authentication' with 'Use same settings as my incoming mail server'.
Thunderbird
IONOS documents Thunderbird on SMTP port 587 with STARTTLS rather than the port 465 it recommends elsewhere.
Sending cold email through IONOS
Per-plan hourly and daily send limits apply. Sign in with your full email address and mailbox password, with outgoing authentication switched on.
Those caps make single-mailbox sending fine for personal mail but a poor fit for cold outreach at volume. Emailchaser spreads sending across warmed inboxes and manages deliverability, so you can scale without burning IONOS accounts.
Other business email and web hosting
Setting up more than one mailbox? These sit in the same category as IONOS.
Common questions about IONOS SMTP settings
What are IONOS's SMTP settings?
IONOS's outgoing (SMTP) server is smtp.ionos.com. Use port 587 (STARTTLS) or 465 (SSL/TLS). SSL/TLS on 465 (recommended) or STARTTLS on 587. Sign in with your full email address and password (or app password).
What is IONOS's IMAP or POP3 server?
IONOS's incoming IMAP server is imap.ionos.com on port 993 (SSL/TLS). If you prefer POP3, use pop.ionos.com on port 995.
Which port should I use for IONOS?
Use port 587 with STARTTLS wherever it's offered, it's the modern standard for authenticated sending. Port 465 with SSL/TLS is a solid alternative. Avoid port 25, which most networks block for client sending. IONOS's recommended value is above.
Why won't my IONOS SMTP connection work?
Check authentication first: Sign in with your full email address and mailbox password, with outgoing authentication switched on. No app password. Set the mailbox password in your IONOS control panel. Then confirm the host, port and security method match exactly, a 587/SSL or 465/STARTTLS mismatch will fail to connect.
Can I send bulk or cold email through IONOS?
Not at scale. Per-plan hourly and daily send limits apply. Providers throttle bursts to fight spam, so pushing cold email through one mailbox hits limits and wrecks deliverability. High-volume outreach belongs on dedicated infrastructure that spreads sending across warmed inboxes, which is what Emailchaser does.
Which IONOS hostname do I use: .com, .co.uk or .de?
Use the one matching the IONOS country site your contract sits on. A US contract uses imap.ionos.com and smtp.ionos.com, a UK contract uses the .co.uk names, a German contract uses smtp.ionos.de. Mixing them produces login failures that look exactly like a wrong password.
Why can my brand new IONOS mailbox only send about 50 emails an hour?
IONOS throttles by mailbox age as an anti-spam measure. You get 50 an hour for the first week, 100 up to day 14, 400 up to day 30, then 500 an hour from day 31. There is no upgrade that skips it; the mailbox has to age.
My site stopped sending through IONOS SMTP and nothing changed on my end. Why?
Since 29 January 2024 IONOS only lets you send with a From address on the same domain as the mailbox you authenticate with. Forms and plugins set to send as an address on another domain now get rejected. Point the From address at the IONOS mailbox's own domain.
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