Issues with sending emails to United Internet services

Since 12 March 2021, we have been aware of problems sending emails to United Internet services. This includes both and GMX. These problems result in the connection being refused by the server there and it is therefore no longer possible to send emails to these services. This is the equivalent of a temporary rejection, which triggers further transmission attempts on the part of NoSpamProxy.

In the meantime, the GMX press office has published a corresponding statement via Twitter. In it, GMX points out, among other things, the possibility of contacting them for the purpose of unblocking. In this statement, they refer to the fact that unknown and suspicious IP addresses have been blocked.

Please use the GMX MailSecurity contact form

As this is not a problem for which NoSpamProxy is responsible, we ask you to use the contact form mentioned above to contact the IT team there and actively request an unblocking. According to our current knowledge, this does not happen automatically. This means that you have to take action in any case.

Please keep in mind that in the default configuration of NoSpamProxy

  • no further attempt is made to send the email after 24 hours and
  • the original sender is informed that the email could not be delivered.

If you want to increase the value of 24 hours, you can set this as described in the Knowledge Base article How to change the delivery attempts.

We are already actively in contact with affected customers of NoSpamProxy Cloud and users of our TCP proxy in order to eliminate this issue.