You have just created an email address with IONOS and your messages are not showing up in your usual email client. The problem almost always comes from the same place: the IMAP and SMTP settings are not filled in correctly. Setting up IONOS IMAP on Outlook, Gmail, or Apple Mail takes just a few minutes, as long as you enter the correct values in the right fields.
IONOS IMAP and SMTP Server: Values to Know First
Before opening any software, note the two server addresses provided by IONOS. The incoming server (IMAP) is imap.ionos.fr. The outgoing server (SMTP) is smtp.ionos.fr.
The IMAP port to use is 993, with SSL/TLS encryption. For SMTP, the port is 465, also using SSL/TLS. Port 143 (unencrypted IMAP) is blocked by IONOS. Any attempt to connect in plain text will fail.
Your username is your full email address (for example [email protected]). The password is the one you set when creating the mailbox in the IONOS customer area. A detailed guide explains how to set up IONOS IMAP on Outlook with screenshots for each step.
Keep this information handy. It is the same regardless of the email client used.
IONOS IMAP Configuration on Outlook: The Automatic Mode Trap
Outlook offers automatic detection of settings when you add an account. With IONOS, this detection often fails. The software tries to guess the servers and gets the port or protocol wrong.
The reliable solution is to switch to manual configuration from the start. In Outlook (desktop version), go to File, then Add Account. Enter your IONOS address, then click on “Advanced options” and check “Let me set up my account manually”.
Fields to Fill in Outlook
- Account type: IMAP
- Incoming server: imap.ionos.fr, port 993, SSL/TLS encryption
- Outgoing server: smtp.ionos.fr, port 465, SSL/TLS encryption
- Username: your full email address with IONOS
- Password: the one set in the IONOS customer area
Validate, then send yourself a test email. If the message arrives and sends without error, the configuration is complete. If sending fails, check that the SMTP port is indeed 465 and not 587 (the latter works with some providers, but IONOS prefers 465 with direct SSL).
Add an IONOS Mailbox in Gmail via Authenticated SMTP
Gmail allows you to centralize multiple addresses in one interface. You can receive your IONOS emails in Gmail and even reply with your professional address. The process involves two distinct settings: receiving and sending.
Receiving IONOS Emails in Gmail
Open Gmail, then go to Settings, Accounts and Import, then “Check mail from other accounts”. Add your IONOS address. Gmail will ask you for the POP or IMAP server settings. Choose IMAP if the option is available; otherwise, use POP3 (server pop.ionos.fr, port 995, SSL enabled).
Sending from Gmail with the IONOS Address
For your recipients to see your IONOS address as the sender, you need to configure SMTP. In the same “Accounts and Import” section, click on “Add another email address”. Fill in smtp.ionos.fr, port 465, SSL, with your IONOS username and password.
Gmail will send a verification code to your IONOS address. Retrieve it via the IONOS webmail or through the already configured client, then validate. The authenticated sending ensures that your messages do not end up in spam for your correspondents.
Apple Mail and IONOS: Why Automatic Detection Causes Problems
On macOS as well as on iOS, Apple Mail tries to detect the server settings as soon as you enter an email address. With custom domains hosted by IONOS, this detection frequently fails. The application then displays “Unable to verify account” without specifying what is blocking it.
Fill in all fields manually, including those marked “optional”. On iPhone, go to Settings, Mail, Accounts, Add Account, then “Other”. Enter your name, your IONOS address, and your password. Choose IMAP.
On the next screen, Apple Mail displays two sections: incoming server and outgoing server. Enter the same values as for Outlook (imap.ionos.fr / smtp.ionos.fr, ports 993 and 465, SSL). The “Username” field expects your full email address, not just the part before the @.
Validate. If Apple Mail displays a certificate warning, accept it. This behavior is common when connecting to a third-party IMAP server for the first time.
Common IONOS IMAP Configuration Errors and Quick Fixes
The majority of connection failures come from three recurring errors.
The first: a password entered in the email client that does not match the one in the IONOS customer area. If you recently changed your webmail password, update the password in every software where the account is configured.
The second: an incorrect port. Port 143 (unencrypted IMAP) is blocked. Port 587 (SMTP STARTTLS) may work in some cases, but port 465 with SSL remains the most reliable with IONOS.
The third: an incomplete username. Some software only displays the local part of the address (before the @). IONOS requires the full email address as the login identifier.
If you have enabled two-factor authentication in your IONOS customer area, check that this security layer is not blocking the connection from an external client. In this case, generate a dedicated application password from the account security settings.
Once these three points are verified, the IMAP connection works in the vast majority of cases, regardless of the software used.