To protect our customers of dangerous e-mail viruses STRATO e-mail servers do not accept mails that are sent from so called "dial-up-accounts".

If such an e-mail is being sent, the connection to the contacting e-mail server will be closed, generating a "5xx-error".

Dial-up-accouts are e-mail servers that are operated behind a dial-in connection. Those are often abused for spam attacks or such.

The dial-up ip-areas are blocked by STRATO - and by many other providers for that matter. Nevertheless, if you wish to send an e-mail to a STRATO account from your own e-mail server, your e-mail server has to come with a steady IP. Those servers are available at any internet provider.

Please contact your internet provider for further information on the server configuration.