Sending Emails is not Possible

Please Note:

The text on this page was translated by translation software. A revised version from our editors will be available soon.

For 1&1 IONOS customers with an 1&1 IONOS email address

Can't send emails? There are several possible causes. Here you will find solutions to common error patterns.

In most cases, you will find the error quickly and can correct it yourself.


You receive an error email (Mail Delivery Notification)?

In this case, the settings on your page are correct. The email was sent but rejected by the recipient. The causes can be narrowed down using the English details from this so-called bounce message.

Check the following causes

  • The recipient's address is spelled correctly.
  • The destination address still exists. If not, try to reach the recipient in another way to clarify this.
  • The recipient's email box is not full.
  • Your email is rejected by the recipient's email server. For example, companies often block emails that do not originate from their own employees. Ask the recipient or their email administrator.
  • There is a fault on the receiver side. Try again later.
You receive an error message from your email program?

Read the details of the error message and look in the program help of your email program or on the manufacturer's website. You will often find troubleshooting tips there. Test the following steps if the program help does not offer you a solution.

  • Security software (e.g. firewall or virus scanner) interferes with or blocks email transmission. Deactivate them for testing purposes.
  • Check your email settings.
  • Avoid using SMTP port 25 (recommended: 587).
  • Make sure that a check mark is set in your email program for Server requires authentication and that your complete email address (e.g. is entered as the user name.
  • Make sure that the encrypted email transmission is activated. If not, please do so. Make sure you have the correct settings for incoming and outgoing mail servers.
The sending of your email still does not work?

If none of the above measures help, please contact our customer service. So that we can help you quickly, please provide
us with the following information:

  • Which email address is affected?
  • Do you receive an error message and if so, which one?
  • Since when has the error occurred?
  • Which email program do you use to manage your emails?
  • If you use the WebMail, which browser do you use?
  • Which operating system do you use?
  • Does this problem occur on other devices, such as computers, smartphones or tablet computers?