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Important Change for Sending Emails with Different Sender Addresses

For Mail Basic and Mail Business

To increase security for our customers, sending emails through our email servers with alternative or empty sender addresses is no longer allowed as of January 29, 2024. Starting on this date, emails can only be sent if the sender address has the same domain as the email account used.

This affects all applications that use IONOS email server settings:

  • Email programs, such as Outlook or Thunderbird
  • Email apps on Android or Apple mobile devices
  • Email server applications, such as Microsoft 365/Exchange or Open-Xchange

Please note that it is not possible to use alternative sender addresses with Microsoft Exchange 2019 provided by IONOS. Changes that are needed for other email servers can be found in the section I use an SMTP relay server, mail relay server or smart host further in this article.

Please Note

If you send emails through your webspace using a script, please note the information in the article: No sending of emails with a different sender address

Example

You set up an email account with the email address john.doe@example.com. This address is also used for authentication on the IONOS outgoing mail server (SMTP). You use an email address from Gmail with the ending @gmail.com as the sender address.

Starting on January 29, 2024, you can only use sender addresses ending in @example.com. Emails with a different sender, such as the @gmail.com used in the example, will no longer be delivered. In this case, the IONOS outgoing mail server (SMTP) sends the following error code:

Sender address is not allowed

Please Note

The part of your email address before the @ sign can still be freely chosen. The part of the email address after the @ sign must be the same for the sender address and the email account used.

What to do

  • If the sender address of your emails after the @ sign is the same as that of the email account used for it, you do not need to make any changes. This is likely the case for most users.
  • If the domain names after the @ sign are different, adjust these addresses in your email program/app, email server, or other software with an email function before January 29, 2024.
  • If you are not sure whether you need to make any adjustments, log in to your IONOS account. Click on the bell icon in the top right-hand corner. Under the notifications, "Action required: Adjust your email settings" will let you know if any changes are required.

How do I check the settings in my applications?

If you send emails with an email account created in your IONOS account, check the sender address in all applications and on every device that you use to send emails. This affects the settings for sending and receiving:

The alternative sender address is still required

To continue using your alternative email address: Set up your alternative sender address as an additional and therefore independent account in your email program. This will allow you to reply with your alternative address without any problems.

You can, of course, also work with automatic forwarding. It is important that the part of the email address after the @ sign is the same for the sender address and the email account used.

I use email forwarding

You created an email address in your IONOS account (as described in the article Setting up email forwarding), which forwards all emails received to another email address.

  • The forwarding address does not count as the sender address. This forwarding will continue to work.

I use an SMTP relay server, mail relay server, or smarthost

An SMTP relay server (alternative name: mail relay server or smarthost) is a mail server that accepts emails from a sender and delivers them to third parties. One example is Microsoft Exchange.

To use it, an email account (relay address) and an IONOS SPF entry must be created in the same domain.

Example: The relay address john.doe@example.com requires an SPF entry under example.com.

You can find out how to create an SPF record in the Help Center article Using IONOS SPF to Improve Email Delivery.

The email addresses that use the SMTP relay server must belong to the same domain as the relay address stored on the mail server.

"Sender addresses" option in Mail Business

The option Sender addresses in Mail Business (top menu bar Webmail: Settings > Email > Sender addresses) will no longer be available as of January 29, 2024.

Sending emails through Mail Business with an alternative sender address is only possible if the part after the @ sign is the same for the sender address and the email inbox used.

Why is this change necessary at all?

Sending emails with alternative or empty email addresses can pose a security risk and lead to other email providers rejecting these emails or classifying them as spam.

The sender address matching the sending email account is an additional security feature, like a license plate number, for example.

I still have questions about the change. Who can I contact?

Your personal consultant or IONOS Customer Support will of course be happy to answer any further questions you may have. After logging in to your IONOS account, click on the speech bubble with the question mark in the top right-hand corner to display all contact options.

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