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Problems with spam lists

Support > Mail > Spam filter – General


  • You cannot send emails, or sent emails are being returned to you with an error message. However emails can still be retrieved without difficulty.
  • With each attempt to send an email, regardless of the recipient address, you get an error message either in the form of a response email or an error message directly in your email program.

For example, the error messages contain the following information (usually at the end of the email):

  • 554 5.7.1 Rejected X.X.X.X we do not accept E-Mail from dynamic IPs
  • Remote SMTP Server Returned: 554 5.7.1 Service unavailable; Client host [X.X.X.X] blocked using; Listed
  • 553 5.3.0 Spam blocked see:
  • 550 5.7.1 Host is on the AHBL - Please see
  • The following addresses had permanent fatal errors ----- (reason: 550 Blocked - see

(X.X.X.X is a placeholder for the relevant IP address, e.g.


  • These messages originate from the spam filter running on the recipient's email server or from the outgoing Hoststar email server.
  • Each spam filter searches multiple global spam lists and checks whether the IP address of the sender is on one of these lists.
  • The current IP address of your internet connection and that of the outgoing Hoststar email server are checked in the process. At least one of these two IP addresses has been found on a spam list that was checked.
  • If the IP address of your internet connection is included in a spam list, but you have not sent any spam emails, the reason is usually that you have been assigned a dynamic IP address by your internet provider, and the previous user of the IP address was sending spam emails. Dynamic IP addresses are usually reassigned every 24 hours.
  • Dynamic IP addresses are usually used for DSL and cable connections for private use. Static IP addresses are generally subject to charge and are used primarily in business. If you are using a static IP address that is found on a spam list, the reason for its inclusion on the list is probably something in your network.


  • Check whether the current IP address of your internet connection is included on a global spam list: Open the automatic or manual version of MXToolBox.
  • The manual version requires the current IP address of your internet connection. You can check the address here, for example.
  • Dynamic IP addresses are often found on at least one global spam list. Follow these steps if you are having problems sending emails:
    • Find out how your internet provider assigns new dynamic IP addresses.
    • For DSL connections, a new IP address is often assigned when restarting the router.
  • If you discover that the IP address of the Hoststar email server is included on a global spam list, you can assume that the server administrators at Hoststar are already working on a fix to the problem. Our support team will be happy to keep you updated on progress.